Salt Stack Reporting - Executing commands based on environment
The answer is that you can't directly. You have to set a grain on the minions first by doing something similar to:

salt '*' cmd.run 'grep environment /etc/salt/minion | awk "{print \"environment: \" \$2}" &gt;&gt; /etc/salt/grains'
salt '*' saltutil.sync_grains
salt -G environment:prod cmd.run 'df -h'