First sorry for my bad English. Im German

Ok. My Problem. My Clan's running a CS 1.6 Server with WC3FT Plugin. We have a lot of funmaps and now ive the problem, that ther is no fun, if there is a orc and the orc throws a grenade. Cause the hole team is dead after the nade.
Now i want to know, if there is a possibilty to deactivate or restrict a specific race (e.g. orc) for specific maps. Is there a cvar i can use?
Please help!
MfG Hoelsch