I want to examine the effect of education(xvar) on prejudice(yvar) (both 1. level variables) moderatet by current regimetype in the country(xvar) (2. level variable).

I am using the most recent data from the World Value Survey to examine the effects of the interaction, my problem is the following:

In order to assign every country a regimescore I have used the Freedomhouse reports from 2012/13 to generate a new "regimetype" variable, and assigned every observation in the data set with the appropriate score (from 1 to 7). My problem is then: how do i aggregate the scores from each observation, to make it a group level variable? Or is it possible just to run the mixed command like
- mixed prejudice(yvar) c.education(xvar)##c.regimetype(xvar2)||regimetype :

I hope the question makes sense.