LDAP Users and Group trouble

I have 4 LDAP Primary Domain Controller(PDC)servers (OpenSuse 10.3) located at 4 different locations. All are connected in a circular form over the WAN. Now The problem is, as soon as I create the user,the user is getting replicated in all the 4 location, also the user can able to login to server via XP client machine. However there are so many groups created inside the LDAP server,to which I am not able to add the user. Many applications are mapped to particular group, so without adding a user to particular group he/she cant able to run any of the application.
Does anyone knows what is the problem. Daily there are about 4-5 new users creation in my organization and without adding them to group they cant able to do anything. I am in deep trouble please help. :’( :’(