2ea. bathroom venting

Nah not going to beat the ventilation dog again, but here is a twist ?

Remodeled both baths in my condo. Both vented to the outside
separately with metal duct above in attic. I disassembled ducts,
installed insulation sleeves to all tubes. (condensation issue)
Now picture a big "Y",. . top is from baths which now meet at a wye, combining into one duct, travel 15ft. as one then go to the
outside thru exhaust flapper.
installed additional baffles at inlets to wye, to reduce possible siphon,
and vacuum. (overkill that's me)
Anyway, I have now connected two baths to a trunk line.
LEGAL? ?? Code says ??
I've seen motels feed to a common trunk line of the same size.
I snitched the one, now extra duct to handle a kit hood vent! :devil3:

I'm in Michigan . . . . . . and its snowing !
whats the verdict?
THANKS