I have an online store selling Sessions.

Each Session has multiple presentations.

A Session Package is made up of multiple sessions.

A session looks up to it's parent, which is a conference object, since we have yearly conferences.

I need a way to associate multiple sessions with multiple packages.

Package1 = Session1, Session2,Session18

Package2 = Session1,Session12,Session14

Package3 = Session12,Session14,Sesson2

I cannot use the master/detail or lookup, that forces me to use too many objects, also, I already have relationships on those objects.

Any ideas on how you would create this package builder?