Allow to set multiple workflows for the group service tag

Problem/Motivation

Some time, we are creating different workflow but some are sharing the same logic and could share the same guards.
Ex: workflows that contains l10n steps (content validation->translation->validation of the translation)
I would be happy to have only one guard for all those workflows:
-Checking everything is translated to allow to validate translations
-Checking everything is validated before being published
-and so on

Note that, I use the same transition id and state id for the "shared transition logic" to ease the coding

Proposed resolution

Allow to have multiple workflows asigned to the group service tag in the guard service definition
(with BC compatibility)

  mymodule.transition_l10n_guard:
    class: Drupal\mymodule\Guard\L10NGuard
    tags:
      - { name: state_machine.guard, group: [workflow1, workflow2] }

Of course, I can use the generic guard (without the group service tag, but it will fire every time...