RadioDJ allows you to assign an overlay track (called sweeper in RadioDJ) to a music track. The file will be played over the intro of the target track.

First, make sure that the music file has an intro and you imported some sweeper files in Sweepers category.

In search window right click and select Edit Track (or double click in Track Editor), and the Track Editor will pop up. Select Sweepers tab and add the desired sweepers to the music track and click save button.

Note: Music files with assigned sweepers will play only the assigned sweepers!