Group Expiration Date

Hi, I was try to find an answer for my question, but without success.. I wanted to ask if it is possible to set expiration date for a group, so all users in this group won't get access after expiration date? "Expiration" works for single user (as a radcheck table attribute), but when I enter it in radgroupcheck, it doesn't work. Do I make a mistake anywhere, or it is just impossible? There are any other solutions? Please let me know, or send me any link, where I could get those info's. Best regards, CoMeC