Parameter dependent, dynamic document parts - is it possible?

Hi,

I'm very new to Crystal Reports, and I have a hard issue to solve.

I have to generate a pdf doc (already works), with a reports, that contains a dynamically changing block depends on a parameter, but the other parts of the document are the same...

My question is: how can I solve that?

I thought I whould add subreport(s) dynamically, but haven't found anything, just the design-time solution...

Can You help me?

I'll need some sample code as well.

I'm using Crystal Reports for Visual Studio 2003

Thank You