Hi all,
I am trying to customize a form with PowerApps ...
I have a list (DocsList) in SharePoint Online with a first multi-selection drop-down column (MultiDoc) and a second multi-selection drop-down column (MultiDoc2), but I need it to offer me filtered elements that depend on the selection of the first column
So if in the first column I select Document A and Document C, in the second column it offers me to multi select Area A01, Area A02, Area C01 ... but not the rest.
To do this, I have created another list (SourceList) that contains a column with the name of the main documents and another column with the name of the corresponding areas, looking like this:

The first combo lets me select multiple elements,
Distinct('Documents and Areas (Source List)',Documento)

but the second only offers me the areas of one of the selections from the first combo (the last selected), not all the possible ones:
Filter('Documents and Areas (Source List)',Documento = DataCardValue9.Selected.Result)

Could someone guide me? I don't have much of a programming idea and I'm just starting out on this.
Thank you very much in advance and greetings to this community.