My view would be that since they have already been housed together, any cross contamination has already happened. Unless you have an easy way to treat them separately (that would be best), I'd probably just do them all together.
BTW, the bigger one in the middle with the magenta base is potentially spectacular. Where did you find it?
Waters gonna get funky pretty fast when they start expelling crap. Just throwing that out there.
you need strong wave for quarantine too but I can't see any water movements in the picture. try to get em strong or stronger waves






