I'm new to Streets and Trips and this forum but what I've done is create an excel file with a separate sheet for each of my 'groups' - Restaurants, Rest Areas, Contacts, and Hotels. I then imported each sheet and individual 'sets' were created for each sheet. The set names were based on the excel file name which in my case was S&T, S&T 2, S&T 3, S&T 4. You can then select one of the sets and then select properties and change the name of the set. I'm not sure if that's what you're looking for - it works fine for my application.
Ray