Wavespot has a useful tool called Tags which can be used to organize your locations. For example, if you are managing locations on the East Coast and the West Coast, you could create West Coast and East Coast Tags and assign the locations that reside in those areas. Then in addition to being able to select individual locations, you will be able to easily select groups of locations using Tags. 

To create a Tag, navigate to User Settings -> Tags. Under Tag Name type the Tag you want to create. Then under Location, select the locations you would like to link the Tag to. Select Save Changes when you are done.