Omit choices in a select_one question based on previous selected choices in a repeat group

1. What is the problem? Be very detailed.

We need to omit choices in a select_one question based on previous selected choices in repeat group with a determined number of repetitions (repeat count = 4). Its important that any of the choices can be selected despite of the order they appear in the form.

2. What app or server are you using and on what device and operating system? Include version numbers.

XLSForm and ODK Collect.
4. What steps can we take to reproduce the problem?

Reproducible example:

Class students

Q1 - Select the class:

A
B
C
D

Assuming that option "C" is selected in Q1:

Q2 - How many students are enrolled in Class "C"?

Number: 32 (example)

2° repetition of Q1:

Q1 - Select the class:

A
B
D

And so on, until all the options are selected and answered.

Please see Duplicate value in repeat group question.

Hi!!
I think the question was not understood correctly ... but in example 5 of the link: https://support.surveycto.com/hc/en-us/articles/360033730073-Guide-to-choice-filters-part-3 it worked very well.