I don't know how it would be for Star Wars RP, but I remember when I was a dev for a DarkRP server, it was something like:
customCheck = function(ply) return ply:GetUserGroup() == "Moderator" end,
However, I'm not sure if customCheck is the correct thing you need, nor do I know if it will allow anyone above "Moderator" as well. (Remember, GetUserGroup() is case-sensitive, so if the role is 'moderator' it must be "moderator").
Edit: After looking around for a quite a bit it seems they're pretty similar (if not the same), is the first line of your custom ranks
DarkRP.createJob( "name", {
? Because if so, put the line I put above at the very bottom (under the category = ) but before the closing }
Like I said, I could be wrong bc I don't know how SWRP works