Is it possible to prevent the import of data that is not in Eloqua in the Salesforce App?

When I import data through the Salesforce App, can I set it to not import data that is not in Eloqua?

For example, there is an A contact in Eloqua, and there is an A contact and a B contact in Salesforce.

However, if you proceed with the import, a B contact is created.

You can write the Where syntax in the app, but this applies to Salesforce.

All I want is to import only the data in Eloqua and update the data, how do I set it up?