Merger of Corporations & Successor Plan

[shERPA]

Professional Corporations A & B are partners in an LLP.  These 3 entities comprise an A-Org affiliated service group.  They sponsor a 401(k) plan for the PCs and the LLP.  All employees are covered and both PCs and the LLP are adopting sponsors of the plan.

They decide to merge practices with another firm.  The assets of the LLP are first distributed to the two partner PCs, then the two PCs are merged into Professional Corporation C.    A and B's shares are exchanged for shares in  C.  PCs A&B cease to exist. 

PC C has its own 401(k) plan.  A&B's 401(k) plan was not terminated prior to the merger.  C would like to terminate it now and distribute the assets to participants. 

Is C's 401(k) plan a successor plan for purposes of 401(k)(10)?   What complicates this is, except for the sole shareholders of A & B, all the other employees were employed by the A&B LLP.  The LLP terminated them, and C hired them as of the date of the merger.  So the employees terminated employment from the A&B plan sponsor.  

IMO C's plan could very well be a successor plan.  By the merger of the corporations, A&B, who co-sponsored their plan, are effectively part of C now, and C is effectively the sponsor of A&B's plan, and A, B and C are essentially one Employer.  The employees who were employed by the AB LLP and participated in the AB plan are now employed by C, who has (perhaps unintentionally) taken over sponsorship of the A&B plan.   So terminating that plan now, C's plan precludes in-service distribution to employees under 59-1/2 who are not otherwise eligible for a distribution. 

Does anyone see this differently.  I've read the merger agreements and believe this accurately describes the merger transaction.