Experiment to see if OptionParser allows options to define other options. Turns out you can!

gistfile1.rb

require 'optparse'

options = OptionParser.new("usage: #{$0}") do |opts|
  opts.on('-f','--file FILE','loads a file') do |file|
    puts "loading file #{file}"

    opts.separator "#{file} options:"
    opts.on('-c','--custom') do
      puts "custom option defined by file #{file}"
    end
  end
end

options.parse(ARGV)

$ ruby test.rb -f foo
loading file foo
$ ruby test.rb -f foo -c
loading file foo
custom option defined by file foo
$ ruby test.rb --help
usage: test.rb
    -f, --file FILE                  loads a file
$ ruby test.rb -f foo --help
loading file foo
usage: test.rb
    -f, --file FILE                  loads a file
foo options:
    -c, --custom