Hi,
Yes you can use 2 dLive MixRacks and 2 Surfaces with a digital split as long as you have the same I/O Port card on each side. You can choose from our range of audio networking cards including gigaACE (128×128 96kHz), Waves V3 (128×128 96kHz), or 48kHz Dante, MADI, EtherSound with the M-DL-ADAPT.
Get in touch with our distribution partner in the US, American Music & Sound, or one of their reps, and they will be happy to assist you in specifying a system: https://www.allen-heath.com/dist_type/usa/
2 Surfaces on 1 MixRack is on the list for future updates but not for the very short term.