I see this is implemented in KSL already so it is possible.
Have various types of lists.
Black - anyone EXCEPT those on the list (for persistent race rules infringers etc!)
Green - anyone regardless
White - Anyone who satisfies a certain set of criteria (age, gender, geographical area, wkg, ftp, etc)
Red - only those from pre-approved squads, clubs, teams etc
Red+ - Only those from Red which have been listed in the pre-race start list. Restricted team size.
That’s just my initial thoughts, honed over 2.5 years and 150+ races!
Kiss Super League already has ‘Red’ listing so hopefully some sort of filtering is coming but Kiss Community League was hopefully going to be Red or Red+ but ended up being Green with post-race filtering. Making it like as if you decide to run a road race and a Sportive at exactly the same time on the same roads…