What you are describing is called a "many to many" relationship. A given laptop record needs to link to many parts and a given part record needs to link to many laptop records.
The typical approach for setting this up is to add a third table, a "join" table that manages the many to many links:
LapTops::__pkLaptopID = Laptop_Part::_fkLaptopID
Parts::__pkPartID = Laptop_Part::_fkPartID
A portal to Laptop_Part located on a Laptops Layout can list all parts for a given laptop and fields from Parts can be included in the portal row. Put the same portal on a parts layout and you get a list of all laptops that require that part and fields from laptops can then be included in this portal's row to show more detail.
Here's a demo file for many to many relationships that you may find helpful: https://www.dropbox.com/s/oyir7cs0yxmbn6i/ManyToManywDemoWExtras.fp7
Many thanks for that!
I will try that solution. At the moment I have set up a script that collects the compatibility within a simple textfield. But the better way would be the relationship way . So many thanks for that hint an the link!