I have built up my covered patio to add fans , lights and coming soon, two 1500watt heaters. I have all of these currently running on a zooz powerstrip and have added IRIS motion sensors around my patio. I also have contact sensor on the back door.
I know that my wife and kids will leave all these devices on when they leave or go inside if left to them.
Most desirable option would be any two of my motion sensors or door contact sensors to trip a "Patio Presence Switch". to on. That switch would reset 15 minutes after the last sensor in the zone goes inactive. Then i can take that switch and run my simple rules for turning on or off various devices in the zone. Does anyone have a solution for this?
If you don't leave the patio door open (or closed, I guess) when you're using the area and not any time else, then I'm not sure how useful the contact sensor will be, though you could use the last open/close event somehow if you wanted. But since you have motion sensors, I'd expect those to be much more useful. You might not have to do anything special with here: all the devices you want to control (either the devices directly or just the virtual switch you want to turn on/off this way) sound like switch-type devices, which the stock apps Hubitat Simple Lighting and Motion Lighting (despite the names) can work with.
You could leave the virtual switch out of the equation entirely and just use those apps (the latter is more powerful, but both let you choose multiple sensors) to directly manipulate your fans, lights, and heaters. However, if you want the switch because you plan to use it in other automations, you could use one of those apps to turn the virtual switch is detected on one or both, then off after a delay of your choice (again, Motion Lighting has a lot more options here--one could only turn it on, one could not turn it on but prevent it from turning off, etc.).
Since all of these (or Rule Machine, if you want to go there instead) are capable of using multiple motion sensors directly, you probably also don't need to do anything special there, but if you do, the built-in Zone Motion Controllers apps may be able to help (creating one effectively virtual sensor that combines the two in one of a few different ways depending on which options you choose in the app).
PS - I'm not sure if your post also means that you're planning on adding these two 1500W heaters to the Zooz power strip, but don't. 
It is rated for 1800W max (presumably 15A * 120V). In fact, that would also exceed the capacity of a typical 15A (or even 20A) residential circuit, so you'd need to run them on at least two different ones. You may already have a solution for this, but I wanted to mention that since it wasn't clear.
Try my Aggregate Motion app in code share
