OK, so here's a situation.
I know these 2 people. Let's call them A and B. They know each other 2 and we all know each other well enough to have an occassional dinner at each others place.
But I also know that A doesn't like B as I have been told that. B may know it but has never said anything and B continues to socialize with A. A hesitates to meet B but cannot refuse because of old ties.
So, do I tell B that A doesn't like you so back off, or should I let them fight their own battles. I like them both and I don't want either party getting hurt.
Maybe if you say something, they will start blaming you for their own problems. That's my experience anyway.
In my opinion it's better not to interfere.