I have a client that is going to have two events 6 months apart. You can register for each event separately, but he wants to be able to offer a discount IF, and only if the people register for both events.
We can add this to our product roadmap. The way projects on the roadmaps are addressed is as follows:
1) Sponsored (paid) projects are given the top priority for resources.
2) Unsponsored projects are addressed based on availability of resources and customer demand.
If all of you need this right away, I could put a proposal together where the cost is split. It would be quickest way and it would be inexpensive for each of you to get this bumped up on the priority list. If you are interested please fill out a support ticket for custom requests and reference Multi-Registration discount so I know that is what you are interested in.