Add Seach Within Query to Data Layer (for Analytics)

We're able to track queries entered into the main Site Search bar via Google Analytics (and Opti Analytics), however, the Search Within keywords are not able to be tracked.

The API call within the main Site Search separates the keyword entered in the Data Layer under the variable "searchQuery" See attached example for 'ball valve'

The Search Within query does not pass the data to a separate variable. See attached example for 'iron'

We request that the Search Within query be treated similarly so that it is accessible via GTM and can be tracked for website improvements.