Unique 2-way switching for a blower?

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Hello, all.
I have an interesting question that hopefully has a simple answer!

I've purchased a "whole house ventilation blower" unit, that's being installed between two bathrooms... one being our bedroom's bathroom, the other located between children's bedrooms.

It's essentially a ventilation fan, but it has one large exhaust duct, and [up to] 4 smaller inlet ducts, that you can run ducting to several bathrooms in a single home.
When the unit is activated, it quietly exhausts from all the rooms at once.

What I would like to do is have a switch located in each bathroom (I'm only ventilating two rooms) to control the unit.

However, I'm not looking for standard 2-way switching like a light -
I would like either switch to be capable of turning the unit on... but only if both switches are turned "off" should the unit turn off.

I don't want to turn the ventilation on, get in my shower...
...and in the meantime, a child gets in their shower, and thinking they are turning the ventilation unit on, inadvertantly turning it off. :wink:
It's going to be remotely mounted (as designed), so hearing it may not be a factor.

Also, being a child's bathroom involved, I wouldn't want them to be able to play "games" with mommy or daddy, turning the unit off on them for spite or amusement. ;)

Fortunately, the child's bedrooms and bathrooms are all in a new addition, just framed, I can run wiring however.
Unfortunately, my bathroom is already built and sealed off, and the switch that's in there has a single 14/2 coming from it... hopefully I won't have to break through the drywall that my wife so recently finished herself... I'd never hear the end of it.... :lol:

I'm picturing a way to wire it in my head, essentially wiring to both switches in parallel, to this blower unit... is it this simple? Is that a method that conforms to electrical code (as this addition will be inspected obviously)?
 
The way you describe is feasible, but without knowing more about the unit it is difficult to be definitive about it.

One way you could do this is with a contactor.

Run the power to the unit via a double pole contactor, then run the coil, or trigger, cables via the two switches in parallel.

So long as one of the switches is in the ON position, the coil will be energised and the unit will run, however if both switches are OFF, then so will the unit as the coil will get no power and thus release the contactor.
 
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