Well... The option is not there in the GUI in 2012, but it can still be set through script. Peer-to-peer is probably your best option. However, you will have to build in conflict handling. Merge is really for separate clients working with their own data and then updating a main database. I wouldn't use it for stuff that is highly transactional on both sides. Still... I am continuing to use Transactional Replication with Updateable Subscriptions as long as it is still available.