With iPMC the fields are defined directly on the entities. If you want to have the same field on multiple entity types you must create each independently.
A concept which I have seen on other PIM systems is to manage field definitions independently of the entities.
A very simple example with 7 definitions and 3 entities
When a field definition is applied to the entity type it is prefixed by the entity name e.g.
Name -> ItemName, PackageName, KitName
Thanks
Mark