Hmm I think that would depend on the types of animals you are taking care of. If they are similar types of animals and get along with eachother then that would probably work. But if they are very different and don't get along with eachother then it's best you only sit one of them. It also depends on how much time, space, and experience you have. Don't take on more than you can handle! :)
thanks for the great advice!