At this point of time, miniDSP platforms don't support Dirac Live Bass Management. Being a software/firmware update, this may change in the future but we can't share much more as per our company policy. In the meantime you can easily handle multiple subs as per the following app notes:
https://www.minidsp.com/applications/audio-streaming/sub-integration-with-shd
https://www.minidsp.com/applications/subwoofer-tuning/dual-sub-with-mso
https://www.minidsp.com/applications/home-theater-tuning/ddrc-88a-multi-sub-optimizer
Feel free to contact us if you further questions.