Can a Commonwealth player use their Battle Plans to support another Commonwealth player?

Question

Accepted Answer

Partly. Follow the rules as written, as clarified by the publisher. When the Commonwealth defends, the defender decides whether battle plans at Commonwealth sites are used, though any Commonwealth player may pay for them. For battle plans in a player's own advisers, that player decides and pays. The designers were still testing variants.

Oath: Chronicles of Empire & Exile

Can a Commonwealth player use their Battle Plans to support another Commonwealth player?