It depends on what you mean by "work with", what version you're using, and whether you have Rio and use Directory Server. There are several previous discussions on the topic that should help answer your question.

1. Saving to a repository: Forms 9.1 allows you to to create connection profiles to multiple repositories using the Save to Repository task (see post)
2. Authenticating Windows users: if your users are AD users, then your users can be configured to authenticate into Forms, regardless of how many repositories they have (see post)
3. Authenticating users through Directory Server 10. As of Forms 10 and Directory Server 10, you can authenticate through Directory Server which support both Windows users and Laserfiche Users created in Directory Server. (see post)

The scenario that remains unsupported is using multiple Laserfiche Repositories for repository user authentication, but it's unclear to me if that's what you're asking about.