extra security layer for few external users

Is there a way to add extra security layer for few external users (not whole company). we have few vendors logging from outside. only when they login, we want to validate their oprid/password also validate their vendor id. Based on which only specific screens will be opened. We don't want to run this validation for non-external users..

Also is there a way we can validate based on the web-profile used for these external users?

Any insight appreciated

We are on FSCM 92, PT 859

Thanks