You can do it via Customize > Keys.
Create a new Lister Hotkey, and set the command to this (I added FROMSEL to the command):
Go FROMSEL NEWTAB=findexisting OPENINDUAL
Getting the hotkey itself is slightly tricky, as the combination of other two keys get in the way of using the UI a bit. But it can be done like this:
- Hold Ctrl + Alt
- Click the drop-down on the right of the hotkey field. Do not release the mouse.
- Move the mouse over Enter in the menu, then release the mouse.
