Hi there, @useraccounts5.
For you to link a product to multiple purchase products, you can use a Bundle item. It is a combination of multiple or Group items you often sell together into Bundles so you can easily add multiple items to transactions.
Here's how to create a bundle item:
I added a screenshot for visual reference.
Here's an article you can read to learn more about bundles: Change Product and Service Types.
You can also use this article as a future reference if you want to apply a bundle item in the invoice: Add bundle item to invoice.
Please know that I'm always here to help, so don't hesitate to reach out anytime. Have a nice day!