First generate your own netgroups-openrc.yaml the original is on github "Artix Linux netgroups/netgroups-openrc.yaml"
Use a pastebin site for your modified file and make sure you save the raw (text) url.
Start The live CD and wait till the desktop loads. Navigate to /etc/calamares/modules and open the netinstall.conf file
Replace the URL found there with yours save and close .
Start Calamares and at the Packages Selection you should see your modified list.
Must Thank Mobinmob for all his help on this topic
Just a quick note it appears packages can only be added or removed from the existing sections.
To add simply insert in any existing section.
To remove replace the - with a # or delete the package completely, you could also just not tick it at the package selection stage.
If you hit the |more| key under your post you can remove it yourself.
I have no delete command under more only modify, report or new and none in modify
Maybe not all boards are configured equally, as on an other area I had just removed a comment when I wrote this.