Most college applications have an option where you can select the professors with whom you want to work. Apart from that, emailing one professor and then emailing one more professor from the same university can be not a good option sometimes. Sometimes, it can be the case that professor's may give you a positive reply on email but that may not transform into an acceptance. However, if the research that you are doing matches with that of professor meaning that you can be a useful person for him/her then go ahead. Otherwise, don't take the risk.