I'm not sure how to ask this - force purchase of a secondary product / configurable option that is inventory tracked?

On 2/21/2022 at 10:14 PM, F3Pens said:

If I use variants, it just creates multiple quantities for the pen which is not what I want since there is only 1 pen available

Squarespace doesn't have any built-in features to do this.

There's a Squarespace Extension available called Trunk Inventory that can do this and although it is easy to set up, you must pay a reasonably high monthly subscription to use it ($35+ per month), depending on the number of orders. 

Trunk works by using Squarespace’s Inventory API, so it would also be possible for a developer to build a solution on non-Squarespace infrastructure. They could also use an RPA tool but they would require a good understanding of APIs, API keys, and/or code to do this. They'd also need to be able to maintain and support it on an ongoing basis - hence the costs of the Trunk solution.