32 groups maximum

Hello. I'm using SuSE linux 7.3 and I have a problem with the passwd and group files (other releases acts the same). I discovered that when i try to make some user to be a member of 32 groups everything is OK,but when i make the user member of 33 or more groups the system ignores the groups greater then 32. No metter how many groups the user is member of the command "groups" returns maximum 32 groups. Please tell me if there is some limit about this and how can I increase this number ? Thanks. Tcvetan Filev AstartecNET Ltd.