Let us assume the name of the Custom Field is A and it is a drop down which is having Options B, C and D. And this Custom Field A is tagged/linked with Projects: X, Y and Z.
The name of the Custom Field (here A) is unknown to us, but we have the list of Custom Field Options (B, C and D) with us. How can we get the list of the Projects (X, Y and Z) from the Custom Field Options (B, C and D)?