Two parts stl - Unable to set config range for the second part

Here is the issue:

I am trying to figure how to slice properly in the event of buying a dual extruder printer (Cetus 2 ou UDP250-300-600D).
For this I made a quick assembly with two parts.
Part 2 is included in Part 1 and I try to create a config range for Part 2.

In Advanced UI mode, when I click “+” I am able to define specific settings for a range into the Part 1 and not for Part 2.

Part 1 in green and Part 2 in blue.

Config range only for Part 1

My goal is to be able to config special settings to improve the quality of the hemisphere especially at is minimum curvature relative to the horizontal plan.

Any clues ?