How change variabile when 2 user leave a gps area?

Hi all, in my home automation project I would like to activate the alarm only when 2 users are outside a certain area. I’m currently using IFTTT location and it works, but only for 1 user only. Do you have experiences for more than one user?
Thank you very much

I’m taking up the topic again as unfortunately I can’t figure out if this is possible or not. I have 2 users on Blynk who have the app installed on their smartphone. I need to change the value of the variable on the device, when both smartphones are outside a certain area radius. I hope it’s clearer.
@PeteKnight can you give me some input on this? You are very helpful.

We plan to add such a trigger to automations, but there is no delivery date yet.