Newman - multiple environment files

Question

When running Newman in Jenkins is it possible/allowed to use multiple environment files for the Newman run... for example, the following, so that the main variables are in the base environment file but then the stack-specific variables overwrite them where needed :

       try {
            sh """
            newman run monitoring.json \
            -e environments/${env}/environment.json \
            -e environments/${env}/${colour}/environment.json \
            --env-var "a=1" \
            --env-var "b=2" \
            --insecure \
            --reporters cli,junit
            """
       }catch (exec){
              currentBuild.result = 'UNSTABLE'
       }

This would then save me having to maintain duplicate big environment files, just for the sake of overwriting a couple of variables.

Alternatively, if you're only allowed one environment file, would/do the env-vars overwrite the value from the environment file?

Thanks in advance!