I guess one way would be to send a webhook to a proxy/server which makes the multiple requests and sends back data (e.g. PHP: cURL) separately or consolidated…
The event prefix in your webhook does not need to be unique, so you can create a separate webhook for each service you want to send the data to, triggered off the same event.
You’ll only need one publish, so the cellular data usage is the same no matter how many webhooks fire on it. For product plans, each service would count as an outbound event toward your monthly limit, however.