Hello. woud love to answer your question. but i really dont understand. it sounds complicated.
The 400x can stream data. thats how simple it is. It does this from a varity of products, like a NAS, a LAPTOP an PC, UB stick, USB HDD.
But it seems u want to control your receiver with the 400x remote??
IF i understand what u mean, u simply want to stream from the HDD that is in your receiver(?), with both of your 400X machines, which are in different rooms? Right?
All u have to do then is to see if that HDD can be shared in a LAN network. If so, great u can simply add that share to the 400X favorites menu and stream the video files.
it all depends:
1. if your satellite receiver is actually capable of sharing it contents on a LAN network.
2. is the video file on the HDD, saved in the correct format that the x400 can play? i.e. MKV, AVI
3. Or can u take out the HDD and attach it to the x400 with the use of an USB casing? (very clumsy way)
Most of your questions have nothing to do with the x400, because the X400 is obviously well capable of streaming content from a NAS, USB, LAPTOP, PC etc...
even if u have a second x400. both machines can stream content, from the same source, at the same time.
PROVIDED that the NAS,PC or LAPTOP is fast enough! i.e. 7200 rpm HDD or SSD.
so the real question is:
Can you share the HDD in your satellite receiver, in your home network?