Actually, you can make a waypoint, but only of type "move" (not seek&destroy, etc).
Instead of using the "domove" command, you should use the "move" command. It's syntax is the same as the "domove" command:
group or unit move position
"Domove" only moves a single unit in a group, whereas "move" actually creates a 'move' waypoint for the group. It doesn't matter if there is only one unit in the group, but if you add more units to a group later, you're going to need to switch stuff anyway.