argument groups enhancement

In the spirit of DRY (not repeating myself), I would like support for argument groups that can apply to one or more subcommands. In addition, a “Global Options” group that applies to every subcommand. Example:

  Naval Fate.

  Usage:
    naval_fate.py ship new <name>...
    naval_fate.py ship <name> move [Location] [<ean>...]
    naval_fate.py ship shoot [Location]
    naval_fate.py mine (set|remove) [Location] [--moored|--drifting]
    naval_fate.py -h | --help
    naval_fate.py --version

  Location:  <x> <y> [--sector=<sector_num>]
    <x>                                     x-coordinate on map
    <y>                                     y-coordinate on map
    --sector=<sector_num>         Which map sector?  [default: active]

  Global Options:
    --verbose                             How verbose should we be?  [default: 0] [max: 3]
    -o --output=(console|email)    Send result to your console, or your inbox? [default: console]

  Other Options:
    -h --help     Show this screen.
    --version     Show version.
    --speed=<kn>  Speed in knots [default: 10].
    --moored      Moored (anchored) mine.
    --drifting    Drifting mine.

[keleshev]

There is no convention behind this, so (I think) this will be more confusing than useful.

[jric]

If you guys agree to incorporate it, I can probably implement it.