Do you know if there is any update on this?
We were recently acquired and have multiple instances, but are looking to consolidate & deduplicate across them!
I saw that it's possible to sync to two different CRMs, but wasn't sure if two instances (SFDC particularly) was yet a possibility?
Also found this more recent discussion, and it seems only possible with middleware at this time: Re: Has anyone integrated multiple SFDC instances to one Marketo?
indeed, with an ETL or middleware, this can be done, but it will have a cost (license, setup, maintenance). But with the free Off the Shelf connector, no it's not.