Groovy script to derive Subscription from a lookup table

Summary:

We have a requirement from one of the customers as per below:

If the Item is ITEM234 (Hardware) then 1st year of subscription and the warranty for that item need to be defaulted as a separate item line. To do that we are looking at maintained a lookup where we will map the Main item (hardware) ITEM234 to a subscription item SUB234 (subscription) and warranty item WAR234 (Warranty) . Based on that we'd like to dynamically derive the subscription lines and Warranty line to the order.

To do this we are looking at leveraging OM Extension (Extend Order Lines) functionality. However, we are struggling to write a Groovy script to derive the subscription items based on a look up code mapping.