[Mediawiki-l] Magic words for user rights?

[billinghurst]

I was looking to have a query that displays output differently based on
the users' group membership. 

I want to display something based on the query like
  api.php?action=query&list=allusers&augroup=inactive&aulimit=500
where a member is a member of a group it will give result A, and if they
are not member of a group, give result B through a {{#switch:}}.

I cannot see a simple way to beyond the api to query for membership, and
thought that there may have been stuff based on the use of magic words and
parser functions.  Am I missing something?  If there isn't the means, if
one isn't a hacker, how can one get the results from queries dynamically?

Thanks.
Regards, Billinghurst