Can Pages do this, and if so how?
Pages > File > Page Setup
Settings > Page Attributes
Format for > Any printer
Page Size > Custom
You are able to define a media geometry that is independent of the media geometry in your presently registered printer.
If you define a media geometry that is larger than the media geometry in your presently registered printer, the system lets you scale down the media geometry.
The media geometry scales as a whole - you can specify the scaling manually or you can let the system compute the scaling (fit once, fit twice - called two up, fit four times - called four up, etc.).
You cannot set multiple origins within the media geometry and manually tile the larger media geometry onto the smaller media geometry supported in your presently registered printer.
This is a limitation of Apple's implementation and not of the underlying printing model.
This is before breakfast coffee, hope my random access memory is working.
/hh