Daft Punk toured with many Voyagers and I’m not certain whether they utilized them as poly synths, however. My experience of polychaining analog monosynths wasn’t worthwhile in the end. The sounds become muddy and it’s difficult to match the synth’s sounds.
With a MIDI splitter, the eight RMEs would play unison. You need something to handle the assignment of polyphonic played notes to the different RMEs. So polychaining is the easiest way. Or find some MIDI tool (soft or hardware) to do this using 8 parallel MIDI outputs.