Unclear help with sets of 3 or more mutually exclusive flags

[glessard]

I defined a set of mutually exclusive flags thusly:

enum OutputBehaviour: String, CaseIterable { case stats, count, list }

struct Options: ParsableCommand {
  @Flag(help: "Program output")
  var behaviour: OutputBehaviour
}

let options = Options.parseOrExit()

The help message that corresponds to these is not very helpful:

$ ./options --help
USAGE: options --stats --count --list

OPTIONS:
  --stats/--count         Program output 
  --list                  Program output 
  -h, --help              Show help information.

The help generator lists them in pairs whenever there are more than 2.
It's not clear that the three flags (stats, count, list) are a set.
It's not clear that they are mutually exclusive.