Hey @Dimo, well your question is pretty complex (in Bubble). When you fetch a list of Events and each Event has a Technician and also a Date Range (a field of date range type), yes, when you compose: Some_List_of_Event's Date Range that’s going to yield you only a list of date ranges.
But that list of date ranges (and any transformed list of date ranges based off of it) still corresponds to Some_List_of_Events, via their indices (as long as you didn’t sort them or something).
So the first transformed date range in the list belongs to Some_List_of_Events: item #1. And the Technician associated with the first transformed is Some_List_of_Events: item #1's Technician.
For example, if we were to display these things in a repeating group, we might set the Repeating Group’s source to Some_List_of_Events. And then, in each cell, if we wanted to display the Technician, that’s just Current Cell's Technician's Whatever. And then, if we wanted to show not the original date range but the transformed date range, we would display Transformed_Date_Ranges:item #Current Cell's index.... (Where Transformed_Date_Ranges is your list of transformed date ranges from Parallels.)
Now, this sort of visual correspondence may not be what you’re hoping to achieve.
If so, that means that what you really wanted to do was recurse over the original Events and transform their date ranges, updating each individual date range field on the Event. In Bubble the best way to do that is to do the transformation when you first acquire the date range.
But I suspect what you’re doing is just some visual formatting (which I suggest how to do in an RG above), yeah?