I have two different projects on my site. One is an internal project and the other is external designed for group members. Currently Each is gathering user authentication information from its own table. The security provider logins were working fine until I added an authentication for the second table (the external one). Now it seems to make all the initial (internal) logins want to look for information from the external table. Do I need to combine the authentication information for both projects into one table that will be used for authentication? I'd rather not.

Hello Hope,
The Security Provider is global for the whole site. So, adding a second instance actually overwrites the first one.
You should store your users in one table and then just set permissions on the different pages, depending on the user's level.