Use data in ADP to validate if a new record is duplicate

Summary:

My setup is like this:

I have a table that is connected to an ADP. The ADP's data comes from an external data source via REST. I am now creating a "create page" and I have to check if the record to be created is a duplicate. I was hoping that instead of another REST call, I can just validate with the ADP. What's the best implementation approach for this?

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