Mating Wire Rope Sheaves

We use a lot of wire rope and one thing that has always givenme fits is the mating of the sheaves. It's obviously simple to matesheaves when the tread is on the same plane/axis. But, if you wantto create an angle in the sheaves then it becomes a bit morecomplicated.

Please view the attached picture.

I need to create a mate where in if I movesheave 1 (in the direction of the arrows) thensheave 2 will will pivot on the big red dot (left of sheavetwo). The big red dot is the rope tread drop. The red line(s)represent the wire rope (hand drawn for illustration purposes). Assheave 1 is movedsheave 2 should angle to maintain the rope tread line.

Now, I can do this with my mouse. If selectsheave 2 it will rotate (as shown by the arrows) on thereference axis I created for the rope drop. I can also movesheave 1 with no problem. However, I can't seem to create amate that will permit me to movesheave 1 and havesheave 2 maintain the rope tread.

The goal
What I am trying to determine is the proper angle to installsheave 2 based on the position I placesheave 1.

All sheaves haveplanes and axises representing the rope tread. What I thinkI need is acircular axis that represents the rope tread around thesheave and create atangent mate between a plane/axis fromsheave 2 tosheave 1.

Any help would be appreciated.
SolidworksAssemblies