>MM creates a user table for each application. I will have multiple, separate applications running on the same network. What is the best way to share a common user table and user grouping table so I don't have to maintain multiple user data sets?

I've never done this, but you might be able to just add another shared database that contains the user security tables + views to the project. Then change the Key field in AppIncl.DBF for the SECURITYDBC_NAME to this new name. That (might) be all you need to do. If that doesn't work, you might also have to redefine the data environment for the security classes to use the other DBC instead.

HTH