Merchant Center requires unique URLs and a unique identifier such as MPN or GTIN. Your product feed would also need to include the subscription offer to Merchant Center.
We are creating a unique URL and MPN that may work for this requirement.
Your subscription app also must be compatible with Merchant Center. From our testing, this mostly means the subscription app must also use a unique URL that loads the specific subscription option. Some apps append a selling_plan=12345 to your URL which should meet Merchant Center’s requirements. If you’re not sure, contact your subscription app provider to see if they do this for you.