Yes.

Of course, almost anything is possible depending upon your budget and/or coding abilities.

As Kevin said, you can have anything possible with Elgg. You can use elgg as master and manage all user registrations and login through elgg or vice versa. It all depends on how expert you are with Elgg and php.

Thank you. I would not be able to do it alone but I now know it's possible.

Love Cherry x x x