Webhook for new transactions only

The webhook configuration in grin-server.toml contains the following:

#The url where a POST request will be sent when a new transaction is received by a peer.
tx_received_url = "http://127.0.0.1:8080/transaction"

However, a POST request is sent for all transactions received, even those that already exist in the mempool. This means that each new transaction can fire many POST requests, as it is received from multiple peers.

Is there a webhook that will fire only when a never-before-seen transaction is received, to eliminate these extraneous POST requests?