It is unclear what you are trying to display in the page footer. Is it standard text that you want to display on all pages where the subreport is printed? Or is the text intended to change on each page, and if so, on what basis? If it is standard text, add a text box to the page footer with the desired text. Create a formula that will be true for all records of the main report, as in {@all}:
{table.customerID} > 0
Then group on {@all}. Insert a copy of your subreport or recreate the subreport (that you have in the report footer) in this group footer (let's call this subreport B) and format the group footer to "New Page Before". Format your subreport A in the report footer by right clicking on it->format subreport->common and uncheck "Keep object together." This will allow the subreport A to immediately follow the group footer containing the other subreport B.
In subreport B, create a shared variable and place it on your subreport B canvas, something like:
whileprintingrecords;
shared numbervar prodid := {table.prodid};
Then suppress all sections of subreport B. Finally, right click the text box containing the desired text->format text->common->suppress->x+2 and enter:
whileprintingrecords;
shared numbervar prodid = 0;
This should cause the text box to only display on the pages containing subreport A (in the report footer).
-LB