TV Links etc. is not my strongest ability, but I can get you going in preparation for someone else helping further.
Firstly, as I understand your post you have the decoders located in the two different rooms.
That setup, and wanting to then share both feeds and control in all 3 locations is going to make for quite a bit of wiring criss-crossing around the house. Your best bet is to first have both decoders in the same room, usually the lounge is preferred but doing so in the main BR (bedroom) is possible. Would you be prepared to consider that?
Sorry if I've misunderstood and both decoders are in the lounge.
The splitter - you'll need to post the make / model. It's clearly capable of passing the HB (heartbeat) signal through it, but it will need to be determined if it can handle the TV Links' power needs.
Maybe one or both of its output connections is labelled "DC Pass"?
All the best with it.
Last edited by Optimist; 2017-02-20 at 10:21.