[siriusmd99]

You can:

register_clcmd("amx_cvar my_cvar", "check_flag")

public check_flag( id )
{
if(!get_user_flags( id ) & ADMIN_IMMUNITY)
return PLUGIN_HANDLED;

return PLUGIN_CONTINUE;
}

put this plugin on the top in plugins.ini and it will block cvar if he doesn't have right flag.