User Authentication

I have recently upgraded our servers (except 1) to Netware 5.1. The problme I’m facing is when I grant mutilpe logins (like 2) users can only login once? If I want any users to be able to login to two different machines at the same time I have to grant 3 logins? It doesn’t matter which container they try to login to. I have the latest server pack applied and am running Z.E.N. works 2.0 (upgrading to 3.0 soon). When I check monitor @ the server I can see they authenticated twice?