[CarCdr]

The maximum number of attachments per post is a site-wide number, as I am sure you know.

To conditionalize it on usergroups, such that a special usergroup was allowed X attachments while everyone else got the AdminCP site-wide limit, would require you to change the script newattachment.php.

In vb 3 and variants, find this code:

if ($attachcount >= $vboptions['attachlimit'] AND $vboptions['attachlimit'])
{
	$show['attachoption'] = false;
}

and BEFORE it, add this code:

if (is_member_of($bbuserinfo, '6')) {
     $vboptions['attachlimit'] = 8;
}

This checks that the current user's primary or seconday usergroups, includes the privileged group '6'. Change this to whatever usergroup you are trying to give this special access to. If the user is a member, then rather than the AdminCP value, the user is allowed as many as 8 attachments.