Multiple owners for commerce order [or] Allow non-owner to pay for an commerce order Scenario:


Drupal site with "Member" and "Spouse" roles.
For any given married couple, Member and Spouse each have their own user accounts.
entity reference field from spouse defines the relationship between the 2 users
an order exists, belonging to Member user (order->uid)


Desired functionality:


Regardless of the uid value for order, allow either Member or Spouse to proceed through checkout and payment for the order.


I realize this is not possible through vanilla Drupal Commerce.  I'm looking for any ideas that will help me figure out how to implement this via existing Drupal techniques, or a custom module.

Specific questions:


Has anyone achieved this successfully?
Are the any specific ways (Drupal techniques) that could help solve this?
What specific hooks or overrides should I be looking at?


Bonus points for elegant workarounds or shortcuts like a simple hook_access override, or a clever way to just-in-time reassign the order uid.
You may want to look at https://www.drupal.org/project/masquerade module for some ideas to see how it does the switching since it allows:


  "...(anyone with enough permissions) to switch users and surf the
  site as that user (no password required). That person can switch back
  to their own user account at any time."


You can then write a custom module.