[thelist] Integrating a discussion forum

[partyarmy]

I have an existing website with an existing userbase. I'd like to
integrate a bulletin board system instead of making my own, but can't
find one that will work with my current setup. phpBB has a plugin that
will import users from a csv file, but that only works if my userbase
is static, and I can't really run the plugin everytime a new user
joins the site. Doesn't seem ideal to have the same users in two
different databases either.

Does anyone know of a way to use an existing userbase with phpBB or a
discussion forum that allows you to use a custom database table for
storing users?

Any help will be more than appreciated.