Set installation Only use my LAN local repository

I create a local repository in my office. This local repository synchronizes every hour with Mirror Tier 2.
And happy to use it every day in all my systems :wink:

Then I have:
For Arch:

for EndeavourOS

I also want to use these URLs on “Arch” or “Endeavouros” installation time, and I need to force the installation ONLY to use these URLs and don’t use the Online repository.

How can I do it in installation time?