Group certain programs on xfce4-panel

This year I am working on projects where I need to have a lot of windows open (20-30 or so) and it becomes a bit unmanageable from time to time.

The xfce4-panel allows grouped or individual window buttons, and I would like something in between. A function to group certain window buttons by program and leave the other ones as individual buttons. That would save me a lot of time that I spend on searching. Thanks and keep up the good work! / Lars