How to Keep Imported SFDC Opp Contact Role Data Updated With Latest Related Opportunity Data?

We integrate with SFDC using the Salesforce Integration App. For our Onboarding and Pipeline Acceleration campaigns in Eloqua, we want to target contacts with specific Contact Roles on Opportunities in specific stages. To support this, we have an import within the SFDC Integration App that pulls Opportunity Contact Role data (primary object) and related Opportunity data. The import writes to a Custom Object table where the Contact Role ID is the unique identifier, since - at least for us - any one contact may be associated to multiple opportunities and may have multiple contact roles on the same opportunity.

Where we're struggling is this: the import will only pull back data when the Contact Role record itself is modified, not when the Opportunity is updated. Thus, large chunks of our Opportunity Contact Role CDO data for the related opportunity is out of date.