Better way to implement different walker menus than just different themes?

My current setup is

.config/walker

------/themes --------/power-menu // i use this with dmenu, it has a different layout.xml -------/starter // app launcher

My starter is the default theme and then I have a script for power menu that I open with:

walker -d -p "power-menu"

My question now is: Can I somehow have my powermenu as a different xml (and css) file IN starter somehow? or does that not work?