Mapping a Lookup Field to a Lookup Field
You can map a field of type lookup to a field of type lookup. When you do this, a situation can arise where there are two records with the same name. In this situation you can use another field to help determine which record is to be mapped. Additionally, it may also be necessary to use the ID of the records to ensure that the correct value is set. The diagram that follows illustrates this:
For further information, see Mapping Fields.