Use the owner of any related object to assign leads in CRM

Let's say I have a data model by which I can attach any converted lead to an account. This attachement could be done using a CRM trigger/workflow or a tool such as Ringlead.

I would like to be able to use the owner of this related object to assign the lead from Marketo, either from the "sync lead" or the "change owner" flow steps.

This could also apply to other lookup fields in the lead or contact objects, such as the source campaign. In this later case, I would use the feature to automatically assign a new lead to the marketing person in charge of the campaign.

-Greg