Well, Couchbase Server is a document oriented database, where it has no idea about the relationships between documents.
What that means in your case is that your application needs to handle the idea of a relationship, whatever that may be. For the simple case it might work (like only one-hop connections), but for things like graph traversal and complex queries, you might be better off using something like Neo4j.
That said, if you more care about your documents and you only have basic uses cases, Couchbase may still be a good fit. Do you want to tell us what you have in mind?