I don't own the set but I have downloaded the profiles and studied them, so here are my thoughts.

The individual profiles are setup as follows:
- Box set  UPC#  (X-Men: 3-Film Collection)
- Alternate UPC#1 (X-Men)
- Alternate UPC#2 (X-Men 2)
- Alternate UPC#3 (X-Men: The Last Stand)

All the profiles have 4K/Blu-ray media type ticked.
All alternate profiles have missing Disc IDs and same covers as Box Set.
Box set contents is blank.
Box set is Digipak with slipcover and Alternates are Digibook.

On the surface, this appears to be a box set containing three (3) different films, but each film is available on both 4K and Blu-ray discs.  In other words, it's a box set containing three combo sets.

I believe the alternate profiles are invalid for the following reasons:

- firstly, the Box Set rules only allows alternate profiles for the scenario when more than one film is on the same side of single disc, there is no mention of alternative profile creation for each film on a single disc with the box set.

- secondly, the rules state we use alternate versions in three scenarios:
1. updated re-release of a title with same UPC/EAN/Disc ID
2. unrelated releases of different titles that share the same UPC/EAN
3. more than one film on same side of single disc

Option 1 is not applicable in our case.
Option 2 is not applicable as the different titles were related by virtue of being in the same release (box set).
Option 3 is not applicable in our case.

I would recommend you go ahead and create the profiles in accordance with the box set/combo set rules. In particular, I would focus on the 4K film discs first, as the Blu-ray disc child profile is optional (as per the combo set rules).

So you should end up with something like this, three 4K childs plus (optional) three Blu-ray grand-childs:
Parent
|--> 4K
|    |- Blu (optional)
|
|--> 4K
|    |- Blu (optional)
|
|--> 4K
      |- Blu (optional)


Some may suggest you add a separate profile for each disc in the box set, that is, you have six child profiles, but I am of the opinion the combo set rule overrules this suggestion.  Just my two cents.

Hope that helps.

I downloaded these a while ago and figured they were submitted this way because the contributor didn't have a 4K player. Unfortunately neither do I but at least the profiles are there to be converted when someone can do it.