How to add a compulsory subscription product as an add-on in Shopify?

Store Design
1
  • Shopify Subscription “add on”

Product A (existing, draft status): TankMate R3 Tank Level Sensor - LTE

Product B (existing, draft status): Annual TankMate LTE (5G) Subscription

We need some customization done on our shopify store as follows:

  1. Compulsory add-on product

  • on page for Product A, a compulsory add-on product is displayed for Product B

  • Both Product A and B are added to cart

  • Customer can only buy product A with product B

Note 1: Product B is a subscription product (using the Sticky.io subscription app)

  1. Optional add-on product (on Product A page): Diamond Hole Saw - 30mm