You don't say how close you are to the members of the group, and specifically this couple, so...
I'd remember that divorce is a war, and that both sides may make unsupportable / untrue claims about the other side because, in a divorce, people think that they have to "win" and that causes them to inflate / prevaricate / generally be nasty.
The party to whom you spoke is undergoing a _lot_ of emotions right now. They're trying to get their mind around it (probably) and possibly they're trying for "revenge" on the STBXspouse.
Also, and take it from me, you most bodaciously do _not_ want to be in the middle. Of a contentious divorce. at all.
So, lessen your emotional ties to the couple (internally, at least), draw back a bit, and do a bit of gray-rocking. That is, listen and give helpful support as if the allegations were true, but don't get all involved in the drama.
That's my view, at any rate. Hope you can get some insight from it.