Two 2V domes will only share one strut, and this will be on the base ring. You could indeed share this strut, but everything else will need interposing struts to make a gateway between the two.
Really the best idea would be to position the domes about 5 feet apart with the doors facing each other. This way they each block the wind for the other, and you can duck between them as necessary. A variant on this theme would use multiple bungie cords between the dome doors to form a shell for a tarp. Not pretty, but functional and durable.
If you need a "hard" connection between them, it will be an ugly, non-geodesic form of tunnel that will require some on-site engineering. Not recommended.
