[Freesteyelz]

My guess is that you want the names to appear in the posbit of the private forum. So try this. Add a (private) Custom Profile Field in Admin CP. Make sure that you've disabled viewing in Members List and Search. After you have finished in the Usergroups option, set the option to "Can View Private Custom Fields". For all other Usergroups that option should be disabled. Now for that selected Usergroup they can enter their names into the Custom Profile Field.

The next step is to set a conditional so that only the selected Usergroup can see the names in posbits. The code can work for both postbit and posbit_legacy layouts. The conditional is as follows:

Anywhere near the postbit or posbit_legacy template Username's column:

<if condition="$post['fieldx'] AND $thread['forumid'] == y AND !is_member_of($bbuserinfo, z)">
      $post[fieldx]
</if>

Where "x" is replace with the Custom Profile Field ID (2 places in code). Where "y" is replace with the private forum ID. Where "z" is replace with the Usergroup ID.

The conditional basically states that if the custom field was entered + it's in this private forum + the user is a member of this Usergroup then the entry will display in posbit. To test it add any text in the Custom Profile Field after you've entered the code and see if that text displays only in the private forum postbit.

I haven't tested it but it should work. If not let me know and we'll easily fix it.