There's no way in MusicBee to separate your long single track into individual songs.
There are two solutions you could consider:
* Use an editing program like mp3directcut to save each song in its own file which can be tagged separately.
* Create a CUE sheet which lists the start and end times of each individual song within your original file. MusicBee will read this and list the song titles separately, even though you still have the original uninterrupted mp3 file on your hard drive.
CUE sheets might be the better option, but I don't use them so someone else might suggest a good program for creating them.
Bee excellent to each other...