Try this:
mapkey qw @MAPKEY_NAMEClose all open windows;@MAPKEY_LABELQuit Window;\
mapkey(continued) ~ Command `ProCmdWinCloseGroup` ;~ Command `ProCmdWinCloseGroup` ;\
mapkey(continued) ~ Command `ProCmdWinCloseGroup` ;~ Command `ProCmdWinCloseGroup` ;\
mapkey(continued) ~ Command `ProCmdWinCloseGroup` ;~ Command `ProCmdWinCloseGroup` ;\
mapkey(continued) ~ Command `ProCmdWinCloseGroup` ;~ Command `ProCmdWinCloseGroup` ;\
mapkey(continued) ~ Command `ProCmdWinCloseGroup` ;~ Command `ProCmdWinCloseGroup` ;\
mapkey(continued) ~ Command `ProCmdWinCloseGroup` ;~ Command `ProCmdWinCloseGroup` ;\
mapkey(continued) ~ Command `ProCmdWinCloseGroup` ;~ Command `ProCmdWinCloseGroup` ;\
mapkey(continued) ~ Command `ProCmdWinCloseGroup` ;~ Command `ProCmdWinCloseGroup` ;\
mapkey(continued) ~ Command `ProCmdWinCloseGroup` ;~ Command `ProCmdWinCloseGroup` ;\
mapkey(continued) ~ Command `ProCmdWinCloseGroup` ;~ Command `ProCmdWinCloseGroup` ;
It will close up to 20 windows but Creo is currently limiting me to 18 windows open at one time.
