Feature Request: Workflow ~ Email triggers only once for each contact, when they book their first appointment

[puneetagrawalils]

Hi,

Is your feature request related to a problem? Please describe.
I would like a workflow where an email can be triggered once once for each contact, i.e. when they book their first appointment.

Describe the solution you'd like
Give an option to trigger a workflow 'once per contact'.

Describe alternatives you've considered
I have created different resources for first aoopintment (which triggers a desired email) and followup appointment (whcih doesn't trigger the email). But it is cumbersome.

feature request