nis (yp) and large group files.

[Jeff Green <jeff@cricinfo.com>]

We use nis to distribute access rights across a group of servers we use
for central functions. The majority of files (around 1,000,000) belong
to a central user and we need a lot of people to be able to modify these
files, this means a large group file. If more than a certain number (or
it may be a character limit on the line I suppose) of users are added to
the group all is well on the ypserver machine but the clients just lose
all info on the group concerned, without any warning. At which point the
website breaks and people yell at me!
Any clues on either what is the limit, can it be extended or an
alternative system to yp?
Thanks a lot
Jeff Green