if u are going for an allosaures tame the easiest thing you can do is lead one into a taming pen and then kill the others outside that way they do not have the alpha pack boost affect and you can easily and safely knock it out
The best way to tame an allo is to find the level that you would like and kill off the rest of it's group but if u want all three just get to some high ground and then just start shooting them with tranqs
A simple way to knock it out is to build a 3Ã—3 room with a gate lure them in with a pachyrhinosarus inside then calm them with the pink stuff and just tranq them make sure to keep them passive to have an easy knock out ;)
If you encounter a pack and only want to tame one of them, you can aggro them onto other nearby wild dinosaurs, and eventually break up the pack. This makes it easier to kill off unwanted Allosaurus and eventually single out the prospected tame.
When three or more allos meet up, the highest level becomes an alpha. He will be the one with orange glowing cloud on his back. Reducing the pack to only 2 dinos will remove alpha status from the highest level allo. This means it is usually easier to kill the weakest in the pack first and then the fight will be much easier. Multiple alphas can be created if a large group of allos form. However that are not invincible. Personally saw a group of 15 Wild allos with 5 of them being alphas get wrecked by a Lvl 80 giga. So even if you could somehow tame all 15, you would be far from invincible. A good step up from a carno, but they stand no chance against similarly leveled Rex or giga.