Hi:
RULES=GROUPS only has to do with the type of interior table lines you see. It has nothing to do with space between the column header area and the first report row.
HEADSKIP (and HEADLINE) were designed for the LISTING or OUTPUT window and are only valid for use in that LISTING destination. RTF, in concept, has NOTHING like HEADSKIP. You could investigate a COMPUTE BEFORE _PAGE_ or a COMPUTE BEFORE <grpvar> in order to write a blank line using the LINE statement -- but short of using either CELLHEIGHT or HEIGHT or WRITING a blank line with a LINE statement or using some kind of native (raw) RTF control string, you don't have many other choices. HEADSKIP is just ignored by RTF. The underlying framework of RTF files is completely different from the type of ASCII text file written for the LISTING destination.
You might work with Tech Support on this question, but your choices are limited to what you can do with RTF output. If HEIGHT or CELLHEIGHT is not working as you expect, this too is something that you should pursue with Tech Support.
cynthia
You can also look at Example 1 in this paper for an idea of how COMPUTE BEFORE _PAGE_ might work:
http://www2.sas.com/proceedings/forum2008/173-2008.pdf