[Groff] Adding printer's marks to documents

[Chris Schaller]

Hi,

Trying to add printer's marks to my roff documents. I stumbled across
groff's graphics commands, but all of them start from current location
and I did not find a command to move the current location to an
arbitrary position.

Is there any way to add those marks to a groff source or do I have to
add postscript code via \X'ps: <I'm lost here>'?

Cheers,
  Chris