Modeling a CRM integration

I'm creating a model of an email marketing domain, and that seems to be pretty solid (thanks to the great O'Reilly book!)... but now I have been asked to integrate a CRM system's content... so my question is how to model the entity "Person" between the two systems. Should there be separate CRM-Person and Email-Marketing-Person entities, or should the CRM attributes be added to the Email-Marketing-Person node? I can see some advantages to having them separate (the relationships are more specific to the domain) but I am also coming from a relational background where duplicating entities is heresy so I would lean towards putting all the attributes associated with a person in one node, and then just creating an "exists in CRM system" attribute to enable reporting. Thoughts?

Do you have a diagram? like the ones from here? It will probably help to see how you've diagrammed the problem. But initially I think you'd be fine
just having one person and then having different types of relationships from your email and CRM.