how to limit users access by groups using radgroucheck

Hi all, I'm new to freeradius and I would like to know if someone can tell me how to limit users access by groups using radgroupcheck. I have made some researchs and I saw that radgroupcheck didn't reject users even if there is a mismatch attribute. I'd like to have a confirmation about this thing if it's true or not. I know with radcheck we can specify attribute like NAS-Identifier or NAS-IP-Address ... to limit user's access but i'm searching for a solution using groups. Can someone help me please? Thx -- RAZAFIMBELO Faliharinohatra