Design question

My company is looking to use PostgreSQL in place of our existing system.
We currently house data for multiple clients. All of their data is
stored in a single database in different schemas for each client. Mosts
clients have multiple login accounts, which we maintain in a
database-specific USER table (contains full name, company, last login,
etc).

Q: is the PostgreSQL pg_user table the appropriate place for these types
of users, or would it be better design to have a generic "client" login
which subsequently references a second USER table?

Let me know if the question is obscure. I'm trying to keep it brief.