In continuation of the question How Many Unix Groups Can A User Be A Member Of?: can I somehow change this limit?
As noted in my comment, the only way known to me is to change the kernel code.
You find the limit inside limits.h.
Since there have been quite some updates to the kernel it might be possible to decrease this limit with some configuration file, eg with the help of PAM.
In Solaris it can be changed in
Where number is between 16 and 1024; a reboot is needed if it is changed.