Wether one or two or even three Sathanas fire their main beams at you doesn't really matter. Unless there is something done with scripting, Rayners and Titans go down from two BFRed hits. And when a single Sathanas can take two destroyers down per beam-salvo, it doesn't matter if there are two or 20 of them lined up.
The only real chance you have against a not de-fanged Sath is hitting them from the sides or from behind.
Every time I see this kind of statement, I wonder how anyone could possibly come up with a
realistic scenario where a Sathanas has a perfect opening salvo opportunity against two destroyers. Hell, even
one destroyer. Every destroyer ever destroyed in canon by a Sathanas has either been anchored to a defensive position or didn't even know the Sathanas existed.
If a Sathanas were truly capable of the kind of precision jumping necessary to surprise GTVA ships with a beam-range transition, they'd have done so against the Orestes. That they did not, while not necessarily being definitive, ranges high on the scale of
retarded for maneuvers if they could have.
Two destroyers and supporting elements, against a fully prepared, fully armed Sathanas
while that Sathanas had the benefit of choosing when and where to engage managed to destroy it with no losses outside of fighter craft.
There isn't a much more definitive scenario than that.