[AccessD] Referencing Fields in Sub-Reports

How can I reference values in textboxes that are located in sub-reports?
I have a report (rptMain) with 2 subreports (rptSub1 and rptSub2).  Each
subreport only contains 1 textbox.  I want to grab the values from each
textbox in the 2 subreports, and display a total of the values on my
main report, rptMain.
I can't figure out how to enter the Control Source of the textbox on my
main report.  With forms, I would just use
"Forms!frmMain.frmSub1.Form.txtTextbox +
Forms!frmMain.frmSub2.Form.txtTextbox", or something of this nature.  I
can't figure out how to do this with reports.
 
Any ideas?
 
Thanks,
Mark Boyd
I/S Supervisor
McBee Associates, Inc.
610/964-9680 x15
 
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