Using Majordomo to manage an existing list

Hello;

We have a set of mailing list we are currently managing with our own 
application. There are about 90 lists representing 90 vendors. Vendors hold 
events with varying frequency. We give our clients the option to sign up for 
a mailing list(s) informing them of upcoming events.

There is an existing java program which sends outs out the emails 5 days 
before an event.

I would like Majordomo to handle subscribing and unsubscribing of users to 
our 90 lists (they are stored in a mySQL DB). I don't want Majordomo to 
anything other than manage the adding and removing of email addresses from a 
mySQL DB. The existing program will continue send out the mails. Can this 
easily be done with Majordomo? Will I have to change our database of users 
to a different format?

Thanks,

Luke