How do I specify a different game system?

I'm trying to create a game that runs using ICONS Assembled, but it doesn't offer me that option, and when I type it into the game field, it helpfully makes it blank. Now, there must be a way to specify things like that--there's even an ICONS character sheet. So how does one specify an "indy" (well, really just unnamed or novel) system? I'd love to try to find players for ICONS or Supers! Revised Edition or Jaws of the Six Serpents, none of which are on the games list, and none of which I can make popular enough to be on the list without specifying them.

Please use "Other Games" from the drop-down menu. Be sure to include your game-system title in all 3 remaining fields: for your Game's Title, Description, and Keywords tagging / game tags. &nbsp;Repeating the game system name in Title, Description, and Keywords, while having "Other Games" in the drop-down, seems to be the best way to get visibility and findability, as well as promoting the presence of the game system for future consideration to be added to the list. Wiki docs, <a href="https://wiki.roll20.net/Looking_for_Group#Create_L" rel="nofollow">https://wiki.roll20.net/Looking_for_Group#Create_L</a>...

Thank you!