Expression for Pick by Object Type by UID or Pick by Nth Istance?

Is it possible to reference an object by UID or Nth Instance via expressions?

I am doing a self collision, and found that you can choose the objects that collided by picking the nth instance. I want to compare some values of the objects, say the X-coordinate for this example, and then pick the instance based on it being higher/lower. I initially thought I could directly reference them by Object(0).X and Object(1).X, but as it turns out, this is the IID.

Is there a way for me to similarly reference objects by the Nth Instance or UID using expressions? This will significantly trim down code, even in this example. Right now I have temporary local variables for the attributes I want to compare. I pick the 1st instance, store it to a temp variable, pick the second, and compare the variable. I understand that you can pick by Instance Comparison, but this would just mean I would have to create the temporary local variables as instance variables. This will be increasingly troublesome if I wanted to compare several attributes.

So, is there a way, or perhaps a better approach?

This post offers the same thought I had, which was to use a local variable for storing events. As mentioned, that would probably be troublesome (more code, more variables) when comparing lots of attributes.

construct.net/en/forum/construct-2/how-do-i-18/pick-uid-expression-59942

I ended up using IID as a workaround, which works in my example. First I pick by Nth (0) and assign that object's IID to a local var, and do the same for the next var. Then i just use the IID to reference them in expressions and easily compare attributes

e.g.:

Object(IID1).X < Object(IID2).X

Still, if anyone knows if it's possible to reference via Nth Instance via system expression or UID directly, I'd like to know how. This will remove the need for the temporary vars.