As far as I can tell, Reports can't do that. If you want to print data in a specific order, you have to develop a report so that it reflects your needs.

The way it is now, you can only specify those pages in "Print" dialog, within its "Print range", you'd switch from "All" to "Pages" and put 1,4,2,5,3,6 in there. Then, hope that print driver is stupid enough so that it doesn't "understand" that it is, actually, 1,2,3,4,5,6 and spoils print order.

• I'd put both "letter" and "data" into the Main section
• In Data Model, create 2 queries: one for "letter", one for "data"
• Let Wizard create layout. It will be ugly, but will put "letter" first and "data" next
• Run the report and verify whether layout looks OK. If so, fine - all you have to do is to make it pretty (because it already works). If not, then
• stretch "letter" repeating frame so that it contains both "letter" and "data" objects. In order to do that easily, group "data" objects first because you might have to adjust what's in the background for ages and experience numerous runtime errors.
• That, I believe, should do the job