referring to a single reference when printing in line...

i am attempting to print some mail

but the problem is that each mail piece has a common sheet

the postscript file is huge because each piece contains the code for the common sheet

i was wondering if there is a way to have the code call a "reference image"

in other words, instead of having the code for this text over and over (and over)

is it possible to simply have a reference in a pdf or whatever and then refer to it "in line"

so that each mail piece simply used the same .pdf calling it each time it was needed

does that make sense?

thanks