Has anyone merged multiple reports into one?

I want to take several .frx and make one .frx out of them.

starting with
a.frx
b.frx
c.frx
d.frx

ending with output.frx which is composed of
one copy of a.frx
one or more copies of (b.frx followed by an associated c.frx - if applicable)
zero or more copies of d.frx

I'm confident it can be done.

Can anyone point me at a good reference for the frx structure?
I used to have a FoxPro Advisor with the necessary information, but I can't locate it.

Rick Liebespach