It's just a matter of playing together in my opinion. When I play with random players, I check out the tank first. If he is a lot below my Item level, I give him a bit more time before I attack anything, use quelling strikes and even if I am AOEing, I take care that my main Focus is the target of the tank and the rest of the group. 95% of the time, this is enough. The rest is mediocre tanking.