Predecessor service, rehires, mergers and acquisitons

[R. Butler]

Co. A acquires in Co. B in 2016.  Co. A's plan grants predecessor service with Co. B for eligibility purposes.  Co. B had a plan that was into Co. A's plan at acquisition. 

John Doe worked for Co. B from 2001 through 2005 and participated in Co. B' s plan.  John Doe is rehired in 2017.  We are trying to determine whether he is immediately eligible.  Co. A's plan document provides that after five consecutive one year breaks in service, rehired participants are immediately eligible if they had any nonforfeitable interest in the Plan to employer money.

Would "Plan" generally include Co. B's plan which at this point has gone away.  My inclination is yes because it was merged into Co. A's plan, but I'm not 100% sure about that. 

Thanks in advance for any guidance. 

[K2]

I guess it comes down to how you parse the language in the document.  You said they needed to have a nonforfeitable interest in the plan.  Did they?  If not, then what does the document say next?  But that said, I'd be inclined to let them in immediately, barring anything specific to the contrary.