Generating custom headers/footers with ReportSmith

Hello all!

If this is not the proper newsgroup, please point me in the right direction.

I need to generate a custom footer in ReportSmith (which looks at a
database I set up).  The group is defined by a specific type of "begin"
record and "end" record rather than the normal change in value of a field.
How can I define a group in this way?  Also, even though the above record
types (specified by a code in a particular field) defines a group, how
do I exclude these two record types from the printout of the actual report?

My only thought on defining this type of group is to define a derived field
along with a global field in the report.  I can then effectively count
the occurances of the "begin" record with this derived field.  This
value will change when the report reaches a new "begin" record.  I can
then have this derived field determine the grouping, even though it
does not show up in the printed form of the report.  Anyone have a
better idea?  If I generated groupings this way, how do I go about
defining a global variable in the report and initialize it at the beginning
of the report run?  Remember that this global variable needs to be
accessed by the macro I will use in my definition of the derived field.