Integration Error - Duplicated Active On Site Metric

We have implemented an 'Active on Site' metric triggered through the API on our SuiteCommerce site. However, we recently added the following script tag:

<script type="text/javascript" async="" src="https://static.klaviyo.com/onsite/js/klaviyo.js?company_id=..."></script>

This script is used to track when users enter the site from an email link. Unfortunately, it generates another 'Active on Site' metric in Klaviyo.

Both metrics are named identically. Is there a way to combine them into a single metric for both actions?

We attempted to pass the metric ID in the metric object at the 'Create Event' API Endpoint, but it resulted in an 'invalid parameter' error."