This is somewhat similar, although what I want to do is allow usergroup ID 20 to view something, yet if they are also in usergroup IP 36, to 
not view the content.  We have a forum section which is automatically promoted after a given number of posts (promoting them to usergroup 20), yet we can revoke that by selection of secondary usergroup 36.  The reason I do this is mainly so we can temporarily disable access without interfering with the automatic promotion of a member to usergroup 20.  In short, 20 is automatic, and 36 revokes 20.
I'm not sure if using an AND would be more appropriate, or some sort of IF/ELSEIF/ELSE loop.
I tried this:
	
	
	
		Code:
	
	
		<xen:if is="{xen:helper ismemberof, $visitor, 20} AND !{xen:helper ismemberof, $visitor, 36}">
<p>show this</p>
</xen:if>
	 
 
but the text still appears, and I get this error:
	
	
	
		Code:
	
	
		Argument 1 passed to XenForo_Template_Helper_Core::helperIsMemberOf() must be an array, null given in /usr/www/.../xf/library/XenForo/Template/Helper/Core.php, line 1344
Argument 1 passed to XenForo_Model_User::isMemberOfUserGroup() must be an array, null given, called in /usr/www/.../xf/library/XenForo/Template/Helper/Core.php on line 1352 and defined in /usr/www/.../xf/library/XenForo/Model/User.php, line 1683
	 
 
Seeing the note about using $visitor vs. $user, I changed the above instances to $user.
	
	
	
		Code:
	
	
		<xen:if is="{xen:helper ismemberof, $user, 20} AND !{xen:helper ismemberof, $user, 36}">
<p>show this</p>
</xen:if>
	 
 
Now, the text does not appear in either case, and I still get the error message.
Is it possible these template conditionals are not supported where I am trying to use them?  I am trying to control viewing of a link in the membercard, along with a link in the user's drop-down menu, using conditionals but have had no luck as of yet.  If they're not possible in these instances, then I can stop beating my head against the wall over this.