Having Alexa send an announcement after a door is left open for x time

Please let me know if this is not the correct forum. This is a Vera Edge controller.
So this should be easy but can’t get it done. I have Google until my fingers bleed but what I find is not helping, specially in creating a virtual switch with switchboard.
So my understanding is I need a virtual switch that will prompt Alexa to send the announcement once the 3 minutes timer in the vera scene expires ( and each consecutive 3 minutes the door remains open), cancel the announcement once the door is closed. I have created the Alexa scene which works with a different system at this time but need new functionality that only vera can provide.
I’m been trying this for 3 days now so I’m burned out, please be detailed as possible.

Thanks.