Is it possible to create an arc which connects to 3 elements tangentially? e.g. an arc between elements but the centre point also touches a third element in the middle. Something you can do in AutoCAD with Circle > 3P > tan snap for each point.
I've attached an example in red of it in AutoCAD.
I believe you could accomplish this with an arc between points with start/end/pass-through and use the tangent snap to pick points. Same with a plain graphics arc using start/end/mid.