It's do-able, but the fishing timers go off randomly, so clicking them all at once would make no sense. Also, the bobber ends up in a random place, too. It's a no-go from that route. I currently have my favorite group multi-fishing with a couple of UI mods and a little understanding of how things work.

Note that I'm hardware boxing, so the only purchase I needed to make was a lousy set of speakers for every machine. Then, I changed the sound that plays when the bobber bobs to say, "one" or "two" or whatever machine the event occurred on. After that, I had to find a place to fish where I could spread the group out so that one character doesn't goof with the other. The reason for that is that if two of my characters are too close together, one will catch a fish and it will sound like the OTHER character caught the fish (because the clients are going to play the "bob" sound if a bobber in range of the character bobs).

That, and I installed FishingBuddy (it's either named that or FishBuddy, I don't recall offhand). That emphasizes the fishing sounds when you're fishing and enables auto-loot as well as double right-click recasting of the fishing ability.

I hope I explained that well enough. It's going to take a little getting used to, but overall I like it because I don't have to keep an eye on every bobber at once.