Of note is that Grevy's (the largest species) is reportedly more cantankerous than the other species and more difficult to mix with antelope. San Diego Wild Animal Park initially had them in the savanna when they opened in the 1970's but had to move them to their own yard. The only zoo where I have seen Grevy's with other hoofstock is Caldwell Zoo (which also has warthogs in the mix, something I have not seen at other zoos either). My local Reid Park Zoo has (or had) ostrich with Grevy's, but not other hoofstock.