I just responded to a thread similar to this.
You can get a new or good second hand top-end home theatre pre-amp. This will drive all your B&O speakers with the latest and greatest Dolby, DTS etc, and also have multiple sources selectable. Yamaha, Pioneer, Marantz, Denon are all good choices. I have the Yamaha CX-A5100.
Most good home theater pre-amps have a "Direct" mode, which is specifically for playing 2 channel music with no coloration to the sound, in your case, the Beosound Moment, if you choose to do it that way. Most good pre-amps have this sort of mode. Now remember, audiophile pre-amps are a little different to home theater pre-amps. The home theater pre-amps are for hooking up TVs, and have extensive Dolby and DTS decoders, and DACs per channel, up to 11.2 channels.
All speakers can be configured to turn on and go to standby with the pre-amp. You can control it all from a single remote or your phone with a top notch universal remote.
Any good home theatre pre-amp unit can do the trick, that will just be your preference. Or any high end home theater receiver, so long as it has has pre-amp outputs. So you would just select your source on your pre-amp/receiver; either your TV, or your Beosound Moment, in addition to several other sources in the future. You can assign "scenes" or "activities" or whatever each pre-amp maker wants to call them, basically its just "groups". One button would activate all the necessary configurations, for either watching TV or Listening to music. You can also distribute/play both the TV and Beosound Moment simultaneously, or to separate rooms etc, the usual stuff.....