What medication have they got?
Please do not separate but treat all piggies with the medication because the companions are already infected. It takes 10-14 days between infection and actual outbreak. If you can catch the companions during that time, you can break the cycle and they will not develop ringworm themselves.
Please follow our hygiene and disinfection measures in the guide really closely. They are absolutely crucial in getting on top of the spores and preventing a return of ringworm anytime in the next two years.
Ringworm: Hygiene, Care And Pictures
We strongly recommend to give all piggies a bath at the end of treatment for the simple reason of removing any spores sitting in the coats so when you then move all piggies into a totally cleaned and disinfected post-ringworm environment, you are making sure that they are not carrying any new spores in themselves.
It doesn't need to be a fungal bath, just to remove any potential spores at the end of treatment. I have had twice carried ringworm in via spores sitting in the coat of new piggies (who were not affected by it themselves); it's a lesson learned the hard way.
I did the whole washing/creaming routine with 16 piggies a decade ago when oral treatment had not yet come in. It was a nightmare bathing all 16 every three days, creaming all the acutely affected piggies twice daily (several of which caught it during treatment from shed spores despite all the bathing, so I had a round #2 as well).
Just consider that on top of all of that I had to wash all the towels from the fungals baths at high temperatures and then all the bedding and cosies during this time as well on top of three thorough deep cleans of the cages and cage areas. It was a total nightmare for a full month.

Only to be confronted with a new outbreak 19 months later - all it takes is one invisibly tiny spore...

This time thankfully, oral medication had come in and I got on top of it so much easier and quicker with less piggies acutely affected (and a LOT less bathing and towel washing, too!) and the ringworm didn't come back. And only two deep cleans with vet strength antifungal disinfectant.
Wishing you all the best. Please read up in the guide on the disinfection and hygiene measures to get on top of all ringworm spores - that is actually the even more important bit.
Ringworm: Hygiene, Care And Pictures
In a healthy piggy, oral treatment gets on top of the acute phase of ringworm within 1-2 weeks. Once producing spores in the crust, a ringworm spot has to run its due course so will be looking worse in the coming days before it gets better. The acute stage is over once no new crust is forming but you want to make sure that it stays that way so please follow your vet's instructions.
Ringworm is not the worst illness (it is generally not fatal) but it is by far the most contagious and species jumping problem you can have in any pet home.
It can turn into a real nightmare because the pesky tiny spores can hang around for such a long time. That is what we recommend to really chuck the kitchen sink at it.
We are here for you on this thread (please bookmark it) for all the little questions and for moral support for as long as it takes. Unlike social media, we do not rely on the number of new threads but we can let a thread run on for as long as needed and give you ongoing personalised support until you are safely past the ringworm outbreak.
It really helps us (and you) to keep all information of one case together so we can refresh our memory and not just give our standard advice but what you really need.