Pie with 2 different fillings
Frankly, I'd be too lazy to fiddle with a "separating wall" shell - partly because unless very well supported its likely to collapse during blind baking anyway.

My tool of choice would be a small cake ring or, in a pinch, a strip of aluminum foil, folded a few times and shaped into a circle.

Place the ring on the prebaked shell, pour the fillings into the inner and outer compartment. Then you have two choices:


Place the pie in the oven, carefully lift the separating ring, bake. The key is that the pie shouldn't be moved after you took out the separation. (Unless you are ok with some "merging"). This is the method I'd choose.
Bake the pie with the ring in place, remove just before it sets. This will give you a clearer separation, but may leave you with a "scar" on the pie. And depending on your filling, it might stick to the ring.


As for the fillings, I recommend that you put the "less runny" one in first, that will prevent a more liquid filling from "creeping under" the ring too much. For very liquid fillings, you might have to hold the ring down a bit, but don't "cut through" the shell!

Finally, note that geometry plays a role: if you use equal parts of fillings, the outer ring will seem narrower than the inner circle. 


For equal amounts of filling, the diameter of the inner circle should be 70% of the whole diameter.  
Alternatively, you could use 1/4 + 3/4 of a recipe to get an inner circle that's half the diameter of the outer.  
For every other case, do the math yourself, remembering that the area of a circle is Pi times radius2. Or that the area grows squared - twice the radius means four times the area or volume. (Height can be ignored, if we assume that this should remain the same.)  
The hacky solution would be to bake two pies and swap the position of the fillings - no math, no need to find or craft a specific ring size. And possibly a nice gift for a friend or neighbor.