Can I use Mac Mini USB outputs for multiple endpoints?

I am transferring from an older Meridian system to Roon. I used to use a Sooloos Ensemble to distribute music around the house. It had 4 RCA outputs and 1 SPDIF one (which goes to a Meridian speaker). There is also a Control 10 and an 861 v6 with a sooloos card. The wiring all goes back to a central rack. I have a MacMini that I am using as a Roon core. I therefore need to have endpoints in the central rack - 4 with RCA outputs and one with an SPDIF one. I had thought that I could use the USB outputs from the MacMini as separate endpoints, but Roon seems to identify all DACs attached to those USB outputs as system outputs, not Roon endpoints. I have tried a Meridian Director; a Chord 2Qute and a Schiit Modi3, They all work fine as system outputs but not as independent endpoints. I have three questions:

  1. Is that the expected behaviour, or am I doing something stupid?
  2. Do I need different DACs that are properly certified with Roon (which ones?), or is my error trying to use the USB outputs in the first place?
  3. If I can’t use the separate USB outputs, presumably I can use one with, say, the 2Qute. What is the cheapest way to create the other four zones - do I need an ethernet switch and say HiFiBerry Digi+ for the SPDIF and Dac+ for the other zones?

Ahh, answer to 1, I was doing something stupid. I had not enabled the individual DACs in Roon settings. When I do so, they can indeed each play independently.

Problem solved…they must be powered on to be seen in roon too.