Company A and Company B are within the same affiliated service group and each sponsors its own 401(k) plan. About half the employees of Company A terminated employment with Company A and now work for Company B. Company A would like to get those participant accounts out of Company A's plan. There's clearly no distribution event. However, can Company A transfer the accounts of their former employees to Company B's plan without the participants' consent (assuming Company B is on board with it)?

Also, should we be concerned about a partial termination of Company A's plan even though the employees are employed within the same affilaited service group?