If you create a Page Header template the lines it contains become "invisible" when Monarch is seeking out Detail templates and should give you the functionality you need IF the report dos not attempt to introduce any blank lines just before a page break or after a page header.
Likewise if it sometimes re-introduces column headers that might not fit well with a page header applied to every page you may have additional challenges.
In those situations you may need to consider some of the less well known techniques that can help. It's not always easy to describe them generically so try the Page Header template first and let's take it from there.
Page Header "invisibility" is my understanding as well. However, my defined Page Header template, which includes the column headings above the Detail bands, does NOT include the blank line separating the column headings from the Detail bands.That may be a "duh".
I'll include the blank line in the Page Header Template, see what happens, monkey around with multiple-line advanced options if required, and report back.
Thanks much, Bruce