I'm playing a Magic format that isn't supported in the picklist. Is it possible to add "Premodern" Magic to the list of Magic formats?

Legal sets and ban list are posted at this site:
https://www.premodernmagic.com/legal-sets#legal-sets

MTG Goldfish did add the option to it's site:
https://www.mtggoldfish.com/deck/custom/premodern#paper