Toggle Wacom pen between eraser and pen

I recently switched from an XP PEN 22" tablet/monitor to a Wacom Cintiq 22. One thing I could do with the XP PEN pen was to set one of the buttons to be able to toggle back and forth between the eraser and the brush tool. You click it once for brush, click again and it goes back to eraser, etc. I really liked this capability. I can't see this option with the Wacom pen. I can only figure out how to set the eraser or pen separatley on just one button. I know I could set one button for eraser and the other for brush but I like having the second button for the Rt Click opt. When I looked for answers on the internet, I found suggestions to set it for eraser and then hold/don't release the button while erasing and then let go and it will return to the pen. This did not work for me. Does anybody know if there is a way to set the Wacom pen to toggle back and forth between the brush and eraser? Thanks