Input key as variable

So I want to set up a variable which takes in input as its value.For example, suppose the variable is inp1 and I assign it to E.So when I use it in blueprint and set it to editable, I can change the value of this variable in every other instance of the blueprinted material. Like say I want to open a door, I use the inp1 as an input variable and use it to open the door. However inp1 changes for different doors. 1 door opens with H and the other with X. And I set the key which opens the door in the inp1.Like in the given screenshot. Is there any way to do that because all I can see is that you have got to select the specific key for every instance.