Passing Subreport Matrix Values To The Main Report

Hello everybody,

I'm trying to pass the values of a subreport matrix to my main report.
For example, I have a matrix subreport like this:

USA CANADA FRANCE GERMANY
Client1Sales $100 $200
Client2Sales $600 $50 $300

What I would like to do is to pass the USA Sales Amount of Client1 (e.g $100) to my main report.
Is there any way to do this?

Thanks in advance for your answers!
Zoz