Combining Topics for PDF from two separate Flare projects

[Limits Tester]

It seems that you can merge projects but not for PDF. I am looking for a feasible approach to combine topics from two separate Flare projects into one PDF output. Here is our situation.

1. We have one core software application.
2. We have additional software applications that use the core application and contain additional features.
3. We have one large Flare project for the core application.
4. We have a separate Flare project for each additional application that is built off of the core.
5. We don't duplicate content. Thus, one guide may make multiple references to the core application guide. (Customers don't like this.)
6. We are working toward a solution using Global linking projects. Until then, is there a way I can generate a PDF that contains topics from two separate Flare projects?

Thanks in advance,

Linda