Attach meter via API?

Summary:

I want to be able to attach a meter template to an asset using REST API.

Content (please ensure you mask any confidential information):

If I add the Item to a meter template and do run the schedule mass update/associate job, it attaches the meter to all the assets with that specific item.

I don't want the meter templates to be associated with all the assets of that item.

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):