Yes. 8 in/out over optical.ADAT? As in Alesis ADAT?
Wouldn’t this require a hardware change to implement ?
There are several excellent solutions on the market: format changers.
For example two I can recommend.
First is MUTEC "Format Changer multichannel aa". A bidirechtional AES/EBU ADAT format changer + sample rate converter.
Second is another excellent manufacturer: rme audio. Model "ADI-192 DD" is an AES / EBU format changer, too. I use it for many years and can highly recommend. Highend equipment (and highend price tag).