use a workflow to change a contact subscription from marketing to no-marketing contact?

possible to write a workflow that will change the individual contacts subscription from marketing to no-marketing contact or vice versa?  

i have one CRM field that determines if a contact sees campaigns or not and would like to automate the marketing/non-marketing designation depending on if that CRM field is yes or no

a NO would put the contact in the NON-MARKETING subscription and a YES would put that contact as a MARKETING contact.

possible to do?

ty