How to trigger a service on only publish later from manage publication in AEM cloud as service.

Hello All,

 I would like to purge the Akamai cache on Publish later from manage publication.

From manage publication, publish now and publish later are pointing to same workflow. we have overlaid the manage publication, because of this overlay columnpreview scheduled page info is not showing in sites console.

In OOTB workflows are hard coded in columnpreview for scheduled workflows.

how can we trigger a service on scheduled page workflow completes. 

we have preview instance, if we go with event handler unnecessary events will be fired. because our count is very high to publish to preview instance. 

Thanks