Honestly, I think they should just do away with max social group sizes altogether for most, if not all, animals, and instead base it on a space requirement- if you've got a massive habitat spanning the ENTIRE ZOO in a wildlife park style setup, there is absolutely no reason you shouldn't be physically able to own a ton of buffalo or zebra or hell, even two prides' worth of lions.
Animal social groups in the wild are known to get absolutely MASSIVE. Yes, some animals should have some limitations i.e. no more than 3 male lions in a social group before they start to fight for breeding rights(because there have been cases of 5 or more male lions co-leading a single pride in the wild) or w/e. Hell, even animals that are solitary in the wild do just fine in groups in captivity- I've even seen tigers housed in groups in zoos, same with cheetahs and many other typically solitary animals.
Basically they should just get rid of the whole "fighting due to overcrowding" thing altogether unless in the case of too many animals in too small of an enclosure, i.e. lack of SPACE.
Yes, territorial animals should be hostile to complete strangers. However, typically animals who are raised together, or fathers and sons and so on, will not fight eachother in captivity. So even animals with a limit on the number of males or whatever should take family relation into account.
Basically, it's simply not realistic AT ALL for group limits to even EXIST in a lot of ingame species. Wildebeest are known to live in herds of 100+ individuals. Yes, I get it, it's a zoo setting, but why should that mean I am limited to a particular group size? Why isn't it dependent on the size of the enclosure, like it SHOULD be?
Fighting for alpha status could be kept as a thing in SOME species that exhibit that behavior. Some bull animals in ungulate herds will behave in that manner, HOWEVER those fights rarely if ever end in serious injury and are JUST for show, to impress the females and assert dominance... not to actually kill. Multiple males can live in a single herd, just one is the "lead bull."
But wolves(and most other animals too honestly but wolves are my best example as I know a ton about them) straight up should not have a limit at all. The only reason wolves ever leave their birth pack is either A. to find a mate or B. because food has become scarce and can't support the large pack anymore. Wolves are not attacked and chased out of their pack, that isn't how it works. Therefore, in captivity, you should be able to keep as many wolves in a pack as you have enclosure space for them. Food is plentiful in a zoo setting, therefore the pack would not separate except for some wanting to find mates, but even then they're not going to suddenly turn hostile towards their family.
Specifically for wolves, and any other species in which pack behavior depends on family relations, they could make it so that the only way to have a pack is to pair two together and have them breed(i.e. all pack members must be family related somehow)... however, even in the wild, some packs HAVE been known to take in strangers, so it'd be nice if there was SOME flexibility there and it wasn't so hard-coded that "introduce stranger wolf, other wolves kill it". Especially since, if you want to KEEP a pack going, you eventually would have to phase out the old breeding pair and introduce a new male or female to the pack for the new "alpha".(even tho wolves don't actually have alphas, but instead 'breeding pairs'... in captivity, a daughter can in fact become the breeding female of her mother's pack once her mother dies and in fact this does happen in the wild as well on occasion)
tl;dr get rid of group limits and instead base it on space requirement. keep alpha fight behavior limited to specific species, and reduce the likelihood of injury as a result, and don't make the fighting constant. Multiple males should be able to live together EVEN IN "alpha behavior" species, just one will be "in charge" and they may OCCASIONALLY butt heads about it.