Hoster does not have an auto rotation feature.
There are some ideas you might find useful
First idea that could help you achieve this:
First enter 3 A-stops in the play list, (Shift+Ctrl+Add Track )
Then enter 3 songs from player A which will go to the bottom of the playlist, then drag 1st song above first A-Stop. second song below 1st A-Stop 3rd song below 2nd A-Stop.
repeat with next singer dragging his 1st song below previouse singers1st song and so on. if you get to another rotation just drag a rotation marker down from the ones that played.
2nd option, enter singers 1st song as normal, then after entering his next song either highlight it in the playlist then press the skip button or if entering his songs via the search window you can tick the box in the dialog to skip the song, same with his 3rd song. Then repeat with next singer. With this way it will play his 1st song then skip to the next singers 1st song. When they have all sung go back to the top of the playlist and un skip each ones next song.
3rd way and how I do it
tell the singers to give you one song at a time, then when they come up to sing take their next song and enter it. This way pretty well keeps it in order. Apart from when singer A wants to sing with singerB
then you have to decide.