Tools for Coding Relationships Between Selections in Images

[kbvatral]

Is your feature request related to a problem? Please describe.
I have been doing a lot of image coding lately and have been wishing for a way to code/annotate relationships between multiple objects/sections/selections in an image. For example, if two objects on opposite sides of an image are related to one another through a code.

Describe the solution you'd like
Could be interesting to see additional annotation tools or a way to link one code between multiple separate selection boxes. My initial thought is like a line or arrow to connect to selection boxes and then label that line with the code instead of one of the boxes.

Describe alternatives you've considered
There are some workarounds. We could select both objects/areas with one large selection region, though this tends to lose a bit of detail in what you are selecting and causes issues with overlapping regions. We could also label each box/region individually with the same code and then write a memo discussing how they are connected, but this is pretty cumbersome and requires extensive tracking of memos alongside codes.

Additional context
For example, I am coding video game level layouts, like the one shown below. I want to annotate a code describing the large physical distance relationship between the fire extinguisher and fire source. Right now, I would either have to use two separate selections with the code or one large selection that encompasses both. I think it might be better to have a way to connect two selections and assign a code to the connection rather than the selections themselves.

[ccbogel]

@kbvatral Hmm OK. I will have to think about this.

Note: we are on the cusp of creating a new release.
This any change for this would be later on - in a 3.9 version.