Multiple Units with Basecamp

We have six Oregon 550t units. These units are identical, so they save photos with identical default names. Basecamp is apparently unprepared for this eventuality, unless I am missing something. Is there a way to prevent the software from saving everything to the same "Pictures/Garmin" in Mac OS? The appropriate photos display for each unit in Basecamp after uploading, but when I try to export the images they are all the same. I can just copy them manually from the units if necessary, but that sort of defeats the whole purpose of having Basecamp to manage things. These units are used for group field trips, so the ideal situation would make it as easy as possible to import everything to one place using different folders/lists for each unit and then upload photos to Picasa.