Turn off edge of window line?

[architect]

Is there a way to turn off the line between window 1 and window 2, so it appears more like

a mulled unit. 
(I would prefer to avoid the ribbon window for a more precise window schedule.)


So, like this:

[Lingwisyer · Accepted solution]

Window / Door Settings => Fixtures and Fittings => Ganging.

Note: Left and right depend on your window / doors opening directions... *facepalm*