assign multiple group to a user

[Mark <mark@giddieup.net>]

exactly how do i assign multiple group to a user..

i tried the memberUid in the group ldif but thats no go..

the ldifs i got are 

dn: cn=users,ou=Group,dc=foo,dc=com
objectclass: posixGroup
cn: users
gidNumber: 100

dn: cn=cvs,ou=Group,dc=foo,dc=com
objectclass: posixGroup
cn: cvs
gidNumber: 500

dn: uid=mark,ou=People,dc=foo,dc=com
objectclass: account
objectclass: posixAccount
objectclass: shadowAccount
objectclass: inetLocalMailRecipient
cn: Mark 
uid: mark
userPassword: password
loginShell: /bin/tcsh
uidnumber: 2000
gidnumber: 100
homeDirectory: /home/mark
mailLocalAddress: mark@foo.com
host: ldap.internal.foo.com
gecos: Mark 


so it only assigns the user to the 100 group, which is the primary group, but how do i add him into the 500 group?


thanx
m