Integration using Sub reports

Hello Experts,

I would like to know how many .rpt files we can integrate in a single .rpt file.

We have 5 Crystal reports and need to integrate in a single .rpt file. Suppose i have 5 reports by name A, B, C, D, E and A being the main report.

I have to integrate B, C, D and E in 'A' report using sub reports concept.

1. Is it possible, If yes how can we do it?

2. If answer is no, how many reports can we integrate in a single report

Best Regards

Sandeep