Example of Group restriction built from the example code for levels

group_example.php

<?php

/**
 * This example is primarily the same as the example code for levels from:
 * http://rocketgeek.com/filter-hooks/restrict-content-by-user-level/
 * 
 * The only real core change was the logic in the check_user_access()
 * function hooked ot wpmem_securify.  The original example had logic
 * that was primarily hierarchial.  This example's logic looks to see
 * if a user has a value or not.
 * 
 * Important note: while this example is simple to set up, especially
 * because it reuses components from a related example, it's simplicity
 * has one drawback and that is that it is not a "groups" example in terms
 * of some users being members of more than one group. This example is
 * only able to set users as members of one group.
 * 
 * The error message in the setup function is a little different than
 * the levels example - it incorporates the example from another post
 * and puts the name of the group into the error message.
 * 
 * To use, one should be familiar with the levels example post referenced
 * above, as well as the groups by category example here:
 * http://rocketgeek.com/filter-hooks/how-to-restrict-categories-to-a-defined-user-group/
 * 
 * This code is a hybrid of those two processes.
 */


/**
 * A simple function to create a settings array
 * for access levels and information.
 */
function my_post_access_levels() {

	return array(
		'levels'  => array(
			/**
			 * Set array values as:
			 * metavalue => label,
			 */
			'group_a' => 'Group A',
			'group_b' => 'Group B',
			'group_c' => 'Group C',
		),
		'default' => 'group_a',
		'user_field' => 'user_category',
		'post_field' => 'post_access',
		'error_msg'  => 'This content is restricted to %s users.',
	);
}

// Remove this if there is no default...
/** 
 * Set the user to the default at registration. 
 */
add_action( 'wpmem_post_register_data', 'set_default_level' );
function set_default_level( $fields ){
	extract( my_post_access_levels() );
	update_user_meta( $fields['ID'], $user_field, $default );
}
// End remove...

// No need to change anything after this line.

/** 
 * Sets up access restriction by User ID and access level 
 */
add_filter( 'wpmem_securify', 'check_user_access' );
function check_user_access( $content ) {

	// Is the content to be blocked and is the user logged in?
	if ( is_user_logged_in() && wpmem_block() == true ) {

		// Get settings.
		extract( my_post_access_levels() );

		// We need the user's ID and the $post object.
		global $user_ID, $post;

		// Get the user's access level.
		$user_level = get_user_meta( $user_ID, $user_field, true );

		// Get the post access level.
		$post_access = get_post_meta( $post->ID, $post_field, true );

		/*
		 * If the user is the correct post access or an admin/super admin
		 * then return content, otherwise return error message.
		 */
		return ( $user_level == $post_access || current_user_can( 'edit_plugins' ) ) ? $content : sprintf( $error_msg, $levels[ $post_access ] );
	}

	// Return unfiltered content for all other cases.
	return $content;
}
	


/** 
 * Add dropdown to post and page meta box for marking level.
 */
add_action( 'wpmem_admin_after_block_meta', 'my_add_post_level', 10, 2 );
function my_add_post_level( $post, $block ) {

	// Get the settings.
	extract( my_post_access_levels() );

	// Get the current access setting, if any.
	$post_access = get_post_meta( $post->ID, $post_field, true );

	// Create dropdown selector of users for access.
	echo '<label>Limit access to: </label>
		<select name="post_access">
			<option value="">Select User Level</option>';
	foreach ( $levels as $meta => $label ) {
		$selected = ( $meta == $post_access ) ? 'selected' : '';
		echo "<option value=\"$meta\" $selected>$label</option>";
	}
	echo '</select>';
}

/** 
 * Save custom post meta for user ID access.
 */
add_action('wpmem_admin_block_meta_save','my_add_post_level_save',10,3);
function my_add_post_level_save( $post, $block, $unblock ) {

	extract( my_post_access_levels() );
	if ( isset( $_POST[$post_field] ) ) {
		// If a user ID is passed to limit access, save it.
		update_post_meta( $post->ID, $post_field, $_POST[$post_field] );
	} else {
		// If no user ID is passed to limit access, delete any meta.
		delete_post_meta( $post->ID, $post_field );
	}
}

redirect_based_on_group.php

<?php // ignore this line

/**
 * Optional filter to redirect user on login based
 * on the group the user has access to.group.
 *
 * Adjust page URLs accordingly.
 */
add_filter( 'wpmem_login_redirect', 'my_login_redirect', 10, 2 );
function my_login_redirect( $redirect_to, $user_id ) {

	extract( my_post_access_levels() );
	
	// Get the user's access level.
	$user_level = get_user_meta( $user_id, $user_field, true );
	
	switch ( $user_level ) {
	
		case 'group_a':
			$redirect_to = site_url( '/group_a_page/' );
			break;
		case 'group_b':
			$redirect_to = site_url( '/group_b_page/' );
			break;
		case 'group_c':
			$redirect_to = site_url( '/group_c_page/' );
			break;
		
	}
		
	return $redirect_to;
}

remove_menu_items.php

<?php

// Add below this line to functions.php

/**
 * This removes menu items based on the user's group access.
 * 
 * Similar to http://rocketgeek.com/filter-hooks/restrict-content-by-user-level/
 * the primary difference is that instead of checking level
 * hierarchy, it just needs to check if the post access value
 * and the user access value match.
 */
add_filter( 'wp_get_nav_menu_items', 'my_remove_menu_item_by_level', null, 3 );
function my_remove_menu_item_by_level( $items, $menu, $args ) {
	if ( ! is_admin() ) {
		// Get post level settings.	
		extract( my_post_access_levels() );
		// Iterate through menu items and evaluate.
		foreach ( $items as $key => $item ) {
			// Get the post access level.
			$post_access = get_post_meta( $item->object_id, $post_field, true );
			// If the user is logged in, check user level.
			if ( is_user_logged_in() ) {
				// Get the user's access level.
				$user_level = get_user_meta( get_current_user_id(), $user_field, true );
				// If user does not have access, remove the item.
				if ( $post_access && ( $user_level != $post_access ) ) {
					unset( $items[ $key ] );
				}
			} else {
				// User is not logged in, if the post has a level, remove it.
				if ( $post_access ) {
					unset( $items[ $key ] );
				}
			}
		}
	}
	return $items;
}

restrict_with_shortcode.php

<?php

// Add below this line to functions.php

add_shortcode( 'restrict_content', 'my_restrict_content' );
function my_restrict_content( $atts, $content = null, $tag ) {
	
	// This should be the option name/meta key for your level field
	$user_field = 'user_category';
	
	// You shouldn't need any other changes after this.
	$current_user = wp_get_current_user();
	if ( array_key_exists( 'level', $atts ) ) {
		$user_level = get_user_meta( $current_user->ID, $user_field, true );
		if ( $atts['level'] == $user_level ) {
			return do_shortcode( $content );
		}
	}
	return '';
}