Good News! The feature does exist and will be enabled some time from now:
"Ah yes, that makes sense. It looks like that feature has been forgotten about after it was disabled in the Rack Pro 2.0 build. We can re-enable it soon after stability testing in a future release. It will likely not work with ASIO but should work with all other drivers.
Andrew Belt"
(I checked with him whether I could quote him)