[Simon Lloyd]

If you only want the kids to EVER see one forum (other than when they aren't logged in but thats another permission story) then put this in your header template right at the very top

<vb:if condition="$bbuserinfo['usergroupid'] == X AND $forum[forumid] != X">
<meta HTTP-EQUIV="REFRESH" content="0; url=PUT YOUR KIDS FORUM URL HERE">
</vb:if>

Change usergroupid X for your kids usergroup number and forumid X for the forum they CAN see, then put the url of the forum you want them to be able to see, should be good to go