Voicemail.conf - serveremail

Is it possible to run a command in the voicemail.conf file to change the ‘from’ email-address. This way the user who gets the email, can reply on the mail just by clicking ‘answer’. I want to do something like this…

serveremail=‘grep “${VM_CIDNUM})” /etc/asterisk/voicemail.conf | cut -d, -f3’

Greetings Jan