When you create a kids related event, use the word kids in order to text the calendar url to your SO/ex/coparent.
This Trigger fires a set number of minutes before the starting time of an event on your Calendar that contains a specific keyword or phrase in the event’s Title, Description, or Location. Ingredient will be based on the zone set in Google.
This Action will send an SMS from your Android device to any phone number you specify.
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Android SMS and Google Calendar