Dropdown with uniques

Hi, can someone direct me to see if what I want to do is feasible with Wix/Velo.

I have a database collection named Liste_Membres.
I already created a form that based on the input of a field, it filters the collection and displays the right data in each field of the form.

On that form, I have fields that are dropdown buttons and would like to have them to work this way:

  • At opening the dropdown is populated with content of the collection filtered by the same filtered field.
  • The dropdown will then display a list of uniques entries sorted alphabetically based on that whole field content from the collection.
  • By selecting a different choice, it will enter it in the dropdown field and then will be saved into the collection with a Submit button.

I find different codes that creates a dropdown button that create a unique list based on the content of a field, but it is used to filter the form. In my case I just want to filter the form based on an input field and offer in the dropdown a unique choice based on that field content and update the field by selecting a different choice and submit to save it to the collection.

Thank you, any help will be appreciated

Pierre