# Capital asset pricing model (CAPM) applied to countries

I'm struggling on trying to find a beta for an equially wighted profolio for three countries (A, B,C).

All the data I'm given are montlhy retunrs of each countrys market indexes and risk free rates for each one as well.

I know whow to apply CAPM to a given set of shares and use a national index (such as the S&P500) in order to calculate betas fo each share, however in this case I have multiple risk free rates an multiple return on indexes so I don't know how to use each piece of information when trying to apply the CAPM.

I'm not using covariance method, but an Excel regression on $x = rm-rf$ and $y = ri-rf$