How to set automatic relationship as a flat level system in Installed Base after placing order throu

Our main objective is to sell the FG product in any combination through sales order but they should appear as "connected to" relationship as a system in the installed base instance automatically.

We have few finished Good product (serialize and Installed Base track able) that needs to be set as a flat level relationship (connect to relationship) in Installed Base automatically. We need to find a way to place the sales order some ways, where all separate lines of FG items should appear in Installed base as a system without Parent / child relationship - only it should appear at the flat level using "Connected To" relationship.