Sync unsubscribes across multiple records

Hello,

  I am hoping that someone has come across this and knows of a simple solution I seem to be overlooking. We have a situation where we may have multiple customer records that share the same email address but are not considered duplicate records and cannot be merged. However, in many countries, SPAM laws are linked to the email address, not the individual that owns the email address. So, if someone unsubscribes, it must unsubscribe that email address, even if someone else is subscribed with the same, shared email address (e.g. marketing@abccompany.com).

Does anyone know of a way to automatically sync unsubscribes across multiple customer records? What I am looking to do is if Jane Doe unsubscribes marketing@abccompany.com, then Marketo will search for all duplicates that share marketing@abccompany.com and trigger a change data value to mark them all as unsubscribed.

If there isn't a way to do this in Marketo, we also use Salesforce.com as our CRM. Could that be an option?

Thank you,

Jason