How to add related features in ArcGIS Online

[MKF62]

I have published a feature service that contains two related layers (relationship class). If I add a new feature (origin) the map and fill out the attributes, the GlobalID auto populates and that is supposed to relate to the ID of the related feature class (destination). But then I go to add a new destination feature and that ID is not carried over through the relationship class. Why not? Or is the relationship class only utilized in ArcCollector?

I have verified that the feature classes are related - when I click on a popup for the origin feature class there is an option to click that says "Show related features" and if I open the attribute table there is an italicized column that has to do with the related destination feature. I just don't get how you add them to map in a related fashion where attributes carry over.

[Nicole_Ueberschär]

What exactly are you trying to do?

This is what I managed to accomplish (on a portal): 

I published two feature layers (Districts and Cells) that are related through a relationship class using the District_ID as the key. 

In a web map I created a new Cell and used a District_ID to relate it to an existing District. 

The relationship is recognized in both directions. 

Maybe the trick is to use the correct identifier for the relationship class?