data-install-1.0.0.php

<?php

$installer = new Mage_Eav_Model_Entity_Setup('eav_setup');

$installer->startSetup();

$inheritBase = 9; // default for product
$attributeSetName = 'Custom Attribute Set';

$installer->addAttributeSet('catalog_product', $attributeSetName);

// Get groups from given set
$groups = Mage::getModel('eav/entity_attribute_group')
->getResourceCollection()
->setAttributeSetFilter($inheritBase) // default attribute set
->load();

// Get possibly existing groups from newly inserted set
$currentSet = Mage::getModel('eav/entity_attribute_group')
->getResourceCollection()
->setAttributeSetFilter($installer->getAttributeSetId('catalog_product', $attributeSetName))
->load();

$aCurrentGroups = array();
foreach($currentSet AS $group)
{
    $aCurrentGroups[$group->attribute_group_name] = array("id" => $group->getId(), "sort_order" => $group->sort_order);
}

foreach ($groups as $group) 
{
    $groupId = 0;
    $sort_order = 0;

    // Check if current group already exists
    if(!isset($aCurrentGroups[$group->attribute_group_name]))
    {
        // Does not exist, create new group and get id
        $installer->addAttributeGroup('catalog_product', $attributeSetName, $group->attribute_group_name, $group->sort_order);

        $newGroup = $installer->getAttributeGroup('catalog_product', $attributeSetName, $group->attribute_group_name);

        $groupId = $newGroup['attribute_group_id'];
        $sort_order = $newGroup['sort_order'];
    }
    else
    {
        // Already exists, use existing ids
        $groupId = $aCurrentGroups[$group->attribute_group_name]["id"];             
        $sort_order = $aCurrentGroups[$group->attribute_group_name]["sort_order"];
    }

    // Get attributes from installer group
    $groupAttributesCollection = Mage::getModel('eav/entity_attribute')
    ->getResourceCollection()
    ->setAttributeGroupFilter($group->getId())
    ->load();

    foreach ($groupAttributesCollection as $attribute) 
    {
        // Add attribute to the new group in the new set
        $installer->addAttributeToGroup('catalog_product', $attributeSetName, $groupId, $attribute->getId(), $attribute->sort_order);
    }
}


$installer->endSetup();