Associate new file extension to specific libreoffice program in macOS

I’m using macOS Big Sur 11.5.2 and LibreOffice 7.2.0.4.

I want to associate a file extension (unknown to LibreOffice, eg “.myfileExtension”) to a specific LibreOffice program.

In my particular case it’s Calc. However, when I do the regular process to associate a file extension to a program using Open With in Finder, the only option is “LibreOffice” (not Calc in particular). If I set LibreOffice as the default program for that extension, LibreOffice opens the file with Writer.

I do not want to change the file extension to some extension already associated with Calc (like, guessing, “.tsv”) because I have lots of this files and I am constantly generating new ones.

So, the question is: How do I get to associate a particular file extension with a particular LibreOffice program (Calc)?

I posted this on a mac forum, and the answer I got is basically “you cannot do that from the mac end”, so here I am at the LibreOffice forum…
Thanks in advanced