Yes, but all the services on a network are interconnected - if one goes down, they all go down, so you only need to add one to your notify list, and check if that one is online. If it is, all the others that exist on the network are also online.
If you are looking for which services exist on a network, I think I recall that when you connect to a network, one of the raw event lines is the one specifying services. I could be wrong tho, can't check that here.