There should be 1:N cardinality (i.e. one recipient can have more than 1 campaign label associated).
The trick is to link the 'campaign label' field in the recipient table to the campaign label table (see the diagram). Every time a new campaign label comes onboard, it will be fed to recipient table and then to the campaign label table.
The use case would be that AC can query recipients based on a campaign label they have received in the past. e.g. only output recipients who have 'campaign01' in the database.
Any idea how the schema would be built or at least point me to the right direction in the AC documentation?