This plugin provides additional features for other plugin. Working as core.
It can check player is in steam group.
sm_swgm_check — force check all connected players.
sm_swgm_groupid — identifier of your steam group.
sm_swgm_timer — interval beetwen checks.
Sourcemod 1.8+
Latest version of SteamWorks.
Put these files into your sourcemod folder.
Open group administration panel and copy identifier then set it in swgm_groupid. (Don't forget cfg/sourcemod/swgm.cfg)