Two (or more) trackers - one callsign

Is it possible to have several trackers using the same callsign on different vehicles, say aircraft, automobile, boat and motorcycle? Only the owner will operate them and one at a time. Is there any activation issue? Is it legal?

It is okay. I am sure someone more knowledgeable on this forum can provide more info, but I have seen several stations with the same callsign. Typically they have added at extension number such as: KJ4FEU-1, KJ4FEU-2, etc.

Look at aprs.fi in a metro area and you will likely see multiple uses of the same callsign in that manner.