any tactics for countering well coordinated survivor teams?

If you're queueing at rank 15, the chance that you are going against a coordinated survivor team every other game is really really low. Chances are, you're just not able to put enough pressure on survivors.

Always focus on macro play - For example, it might seem quite obvious but after you hook someone, you can deduce that 1 person is on the hook, 1 person is likely going for the save, and 2 people are on gens. With that information, you should decide whether to contest the unhook or contest the generator. (Do you know what generators are being worked on? Are they too far to contest? Do you see scratch marks around the hook?) After a while your macro play should improve a lot and will help you a lot in pressuring survivors.

Also try not to overcommit to chases and focus on the weak link.

TheClownIsKing

That's a pretty interesting tactic, pretend to tunnel right off the hook to entice someone to come in for the body block to get a quick new target. I'll have to try that out in my games today

This is a good point. Also if they are running Object of Obsession they do want your attention and may be that expert looper you cannot afford to loop. Time management is king!

What I'd suggest is don't look at killers that you think will be amazing to play atm. Look past the killer at their perks.

Killers like Clown and Plague aren't considered A tier killers but have A+ tier perks.

What I'd say is level these 2 killers first (Probably Clown before Plague). Next is buy Monitor and Abuse from the Shrine (or level up Doctor). Lastly look at what killer you like and level them up. This way your killer will have access to Corrupt Intervention, Pop Goes The Weasil, Infectious Fright, Bamboozle and Monitor and Abuse. All of these perks will help you immensely as killer.

Actually the dev stats last year indicated that on average 55% of games include a 2-, 3- or 4- person swf. It's a safe bet all those swfs are on comms as well. Now how good those swf players are and how coordinated they actually are can vary quite a bit, I've definitely gone against some pretty terrible swf players (e.g. they just immediately run in for rescues or badly timed flashlight saves because their friend is yelling for help in their headset). But at least in terms of how often players are in swfs in general, groups that include at least some swf members are more common than all solo groups.

In addition to other advice above, I'll say that the one weakness of swfs, at least ones that aren't great players on their own, is they can tend to be overly altruistic. They really, REALLY don't want one of their swf friends to get killed. So if you're against a swf you can keep in the back of your mind to expect them to possibly try all sorts of risky rescues, flashlight saves, headons, pallet saves and so on. Basically if you down one of them and you're extra prepared for that you can get a lot of free hits.

Of course the best swf players don't do that, but if you're rank 15 you're probably not going against the best players.

Right. That's why I said it's really rare to go against a coordinated SWF at Rank 15. SWFs are common, but coordination isn't at that rank. People still lack basic understanding of the game to understand what they should be doing. There may be one decent player, but that doesn't mean the game isn't manageable.

Which killers/perks do you have available? I have some really effective builds but they won't secure more than a 1 or 2 kill which is fine because most SWF that are that coordinated consider a single kill a loss and will try to get all 4 out above all else.

One to get as a teachable asap would be Mad Grit. This is on EVERY anti bully SWF build I have. All the body blockers and attempted hook sabotage become slugged very quickly.

Calling swf comms "the 5th perk" has a nice ring to it.