What I assum you are looking for here is that you never start a new group on the back page of the two side page and that you always want a new group to start on a new page. Corrrect?
Do not reset the page number. That will throw this process off. If that is a report criteria let me know because this process wouldn't work if you did that.
Don't bother placing the page number in any group footer. You don't have to have it there to use it as a condition.
(As an FYI using page N of M can really slow down a report if it is large).
In the section Expert highlight the GH1
Click on the formula field next to the New Page Before and put in the formula Not onfirstrecord
(do not check the box just put in the formula)
This will make it go to a next page before it starts a new group header except for page1 (not onfirstrecord).
highlight groupfooter1
Click on the formula field next to the New Page After and put in the formula pageNumber Mod 2 = 1
(do not check the box just put in the formula)
This should make it create a new page after the group footer only if that footer falls on an odd numbered page. If you reset the page numbers after each group it is always going to be considered page 1 regardless if it is the front or back of your paper.
This should work. I tested the concept and works fine in my sandbox report.
Basically this is what you have...
If your group ends on page 1,3,5,7,etc. it will start a new page after the groupfooter (your conditional new page on after GF on odd pages).
This pushes the group header to page 2,4,6,8,etc.. Since you also have new page before the group header that should move it to page 3,5,7,9,11,etc. leaving page 2 blank before it starts printing.
Hope this makes sense