Can I use one thread toward multiple trades?

In earning of a trade... do those threads need to be totally unique per trade? For example... Warden/Warrior = similar, and in two threads, by fighting with a LW on OS turf she is

...fighting for the pack as the need arises, presenting an offensive front to complement the defense the Wardens provide.

but also

...dealing with wolves at the borders and defending the pack's territory during combat to complement the Warriors' efforts.

Just wondering if in earning the trade the thread needed to be unique :)