Not sure I know how to achieve the above to be honest – how would I get it to recognise my WIIM Pro as a video source? Also would this mean re-wiring the DIN socket?
It should just work. The BL1611 automatically configures itself as a videomaster because there is no other video product on the ML network. Selecting any video source (on the BL3500 or BS4) will then select the BL1611’s AAL socket as the active (sound) input. Although I said that the AAL input uses DIN pins 3&5 as the input, this is a standard used elsewhere in the hifi (incl B&O) world and leads such as this are readily available.
Using such a setup, you should be able to solve the other problem by having your Beogram connected to the BS4 (activated with A.AUX, albeit a bit of a faff from the BL3500), and the WIIM Pro connected to the BL1611’s AAL socket, activated using any video source button.
