New to clicker training - have 2 dogs - do I need multiple marker words

I am just crossing over to clicker training.  I have two dogs.  Of course, formal training sessions will be with one dog at a time. So neither dog will hear the clicker or marker word without receiving a reinforcement.  But should I have two different marker words, one for each dog.  So when they are together and one does something I want to mark, that dog knows I am marking what it just did and the other dog does not get, either marked for doing something I do not want it to do, nor hear the marker word but receives no reinforcement.