Best Practices for Managing Contact Communications in Marketo and Salesforce Integration

Hi everyone! Can anyone point me to resources on contact management? Many of our CSMs have reported that communications aren’t always reaching the right contacts. Currently, our Marketo setup can filter by country, product subscriptions, and primary point of contact (POC) to narrow distribution lists. When we use the POC, the communication goes to only one contact per organization--which doesn’t always match CSM expectations. If we don’t use the POC filter, the message goes to all contacts attached to the account, which we also want to avoid. I’m considering adding additional fields in Salesforce that could feed into Marketo, but I want to avoid adding unnecessary fields. Any guidance or best practices would be greatly appreciated.