Is there a way to create a smart list in Marketo that includes all the leads that are manually shared with an SFDC user? Looking to send a campaign not only to leads a user owns, but also to the leads he/she is shared on.
May be you could map the sharing info from SFDC as a custom object in Marketo. If so, from this, you will be able to use the custom object in filters. If this can be done, the hard point might be that the same object will show on lead, contacts and accounts. And you will be able to map only one of them.