I have a need to print two copies of a document on paper from two
trays.
I'm using VC6 and MFC.
Both options need to produce a single pile of paper on the printer -
either collated or interleaved.
Tray 1 and 2 will contain different paper types.

Option 1 - collated
page 1,2,3,4 from tray 1
page 1,2,3,4 from tray 2

Option 2 - interleaved
Page 1,1 from tray 1,2
Page 2,2 from tray 1,2
Page 3,3 from tray 1,2
Page 4,4 from tray 1,2

Option 1 is easy - just print twice and force the correct tray.
Option 2 is a problem - Without producing a lot of single documents (8
in the above example), is there any way I can force multiple tray
selection for each page.

Hopefully, the customer will not require 3 trays !