How to concatenate outputs to win 7 fax printer?

On win 7 sp1 64bit.

Is there a way to use the fax "printer" (MS SHRFAX) to concatenate documents to be sent in a single fax?

For example, suppose I want to print a cover letter from LibreOffice to 'fax', then append another item from LibreOffice by printing to 'fax'?

When I do this, I end up with 2 independent faxes as far as I can tell. I want subsequent prints to 'fax' to append.

In other words, after the first print to the 'fax' printer, I want subsequent prints to the 'fax' printer to append their output to the same fax. (Until the fax is sent or dismissed, or otherwise inactivated, of course -- not forever!)

I know there are other ways I can do this, for example by creating a single pdf or even maybe xps of everything, but what I'm wanting is much more convenient.

Thanks.

I don't think you're understanding the question.

There is a printer I can print to. That printer is called "fax." That is because it does not print to a printer, it prints to the fax printer port. When I "print" to that printer, a new fax is created. When I print another document, another new fax is created. I want only one fax to be created, containing both documents. This has nothing to do as far as I can tell with anything about how many pages I might want to send from the fax application.

Thanks for trying.

But, (1) I don't see why you have to know WHY I want to do something. I asked HOW to do something. WHY I want to do it may be an item of curiosity, but I don't see how it's related to HOW to do something.

(2) You apparently have never had to fax 2 different documents in the same fax? Well, I guess you said you almost never fax.

Oy. I would say there was no reason for you to post 2,4, or 6. You didn't understand the question, but you gave a useless answer, which was actually a question. Then you said you didn't have an answer. Then you didn't like my questioning why you need to know WHY I want to do something when you don't even know the answer. My suggestion: don't post an answer if you don't know the answer.

The reason I made the post about "WHY" is that a typical response on user forums is of the form "I don't know how to do what you want to do, but why would you want to do that?" Then followed by some non-sequitur way of doing something else, often with an implication that the OP is a fool for wanting to do what he wants to do. I thought that didn't happen on this forum, but apparently I was naive.