Add Pages to Existing PDF file by printing to PDF from an application?

Hi All

First time poster here so I hope someone can help me out with this question. I have been searching through the forums here and on google but so far cannot find a solution to what I am trying to achieve. What I want to do is pretty simple so here goes:

Is there a way to create a PDF file from an application, by print to PDF, and then instead of it creating a seperate PDF file, have the resultant pages appended as new pages to an exisiting PDF file?

For example:

I have a file named "Email Archive - Subject X.PDF" containing several pages.

Now, everytime I receive an email which is relevant to "Subject X" I want to print the email from Outlook as a PDF file and have this PDF automatically added as new pages to the file "Email Archive - Subject X.PDF".

The idea is to have a single PDF file containing all the email relating to a paticular topic. Is there somehow a way that when creating a PDF file you can have options of:

1. Create new PDF file

or

2. Add pages to existing PDF file - Select File - add pages

Any ideas on a simple way to achieve this without having to create the PDF file first and manually add it to the main PDF file?

All help, comments and thoughts on this are very much appreciated.

Thanks

Peterjung