Code:
<if condition="in_array($bbuserinfo['usergroupid'], array(6))">
simpilfies to
Code:
<if condition="$bbuserinfo['usergroupid'] == 6">
So "primary usergroup is not 6" would be
Code:
<if condition="$bbuserinfo['usergroupid'] != 6">
If you want to check secondary usergroups as well, I'd suggest to use
Code:
<if condition="is_member_of($bbuserinfo, X)">
and
Code:
<if condition="!is_member_of($bbuserinfo, X)">