That would fall under the aformentioned "amalgamated" interfaces. In Rack you can (theoretically) plug or unplug new interfaces with a different sample rates an

That would fall under the aformentioned "amalgamated" interfaces. In Rack you can (theoretically) plug or unplug new interfaces with a different sample rates and block sizes without rebuilding your virtual interface, since they are treated as individual streams (one per Audio Interface module) instead of being multiplexed and synchronized. But I haven't reviewed the source for thread-correctness and tested carefully enough to deem multiple interfaces stable, so in practice, you might get jitter, crackling, crashes, etc. if you use this feature. Some interfaces work flawlessly though.