Tag protection

I am looking for a program or somewhere to link to to protect a clan tag being
used by non-members. The reason for this is we are getting a number of imposters
playing on various servers under the clan tag and as childish as it seems abusing and
miss -using in game. This is ofcourse reflecting on the clan who as a whole wish
game play to be pleasurable for all and this tag abuse is giving us a bad rep.
I know there used to be some such program with half life which used the HL software
under WON servers.
Please help me make gaming a better place?

wich game ?
and what you wanna do exactly ?

The game is GHOST RECON and all add on packs
As explained in first post we wish to stop other people using our clan tag unless they are actual members therefore not bringing the clan name into disrepute. Obviously we can kick people who play in our own created games as we know who is who but we need to apply it to a main server (ie gamespy) so that it cannot be used by other players or should i say other losers.