richardvanhook

final String NEW_FREQ_FOR_ALL_GROUP_MEMBERS = 'P'; //P=>On each post, D=>Daily, W=>Weekly, N=>Never
final String GROUP_ID = 'CHANGE_ME';  //select id,name from CollaborationGroup

final List<CollaborationGroupMember> members = [
    select id, NotificationFrequency
    from CollaborationGroupMember
    where CollaborationGroupID = :GROUP_ID
    and NotificationFrequency != :NEW_FREQ_FOR_ALL_GROUP_MEMBERS
];
if(members != null && members.size() > 0){