You cannot "migrate" / move an already configured SDS with it's devices and data into Fault set.

You can add new SDSs into the fault sets.

tomer_(engineering_qa) is right.

But just to give you a different angle, if you have enough SDSs / free disk space, you can remove SDSs from your current single fault set and re-add those as new members for new fault sets. It may need several waves, but you can end up with your desired layout without downtime or need to reinstall anything.

Rafa is right, but this should be done wisely and carefully...

Another option would be to replicate / backup all your data, re-configure your SIO system with Fault sets and then restore the data back.