Simple Positional Motor Question

So I have a motor connector connecting a block to a cylinder (think of them as a person with a bat). I want to hook up the left stick to move the motor left and right. The twist is that when I let go of the stick, I want the rotation to stop at whatever point it was currently at instead of resetting to it's neutral position.

For a rotator this is easy, just hook up the left stick X output to the rotation speed (where -100 rotates left, +100 rotates right, and 0 just stops all rotation). But the motor connectors don't have the same rotate speed option as rotators, instead all we have to work with is positional input (which is -100 all the way left, 100 all the way right, and 0 snaps back to the middle).

I basically want a motor connector to behave as a rotator. Is there a clean way of doing this?