Union re-hires and seniority

[hummer]

What is the name of your state (only U.S. law)? Indiana[font="Fixedsys"]
I work for a unionized business(A) that is partnered in a separate unionized business(B) next door. The two businesses(A)+(B) are separate in every sense, except for sharing the same union. These two are operated as separate entities with separate contracts, separate seniority lists, and no bumping or bidding between plants. When the business(B) next door downsized, the union and management from our shop(A) allowed layed-off workers from (B) to be re-hired at our shop(A) (without consulting the employees of (A)) and keep their seniority from the shop(B) next door. My question is, how can we continue to be employed at (A) but lose seniority. Would a lawsuit or some type of injunction be feasible to stop this?

[CraigFL]

Since you are covered by a union contract for your specific business I assume, you will need to refer to it to see how this is handled.