As long as you separate from Company A the year in which you turn 55 or later, and keep the money in Company A's 401k, you qualify for the Age of 55 rule for Company A distributions. Company B or C distributions do not qualify.

IRS does not care about future employment. Sometimes you hear the mistaken belief that you have to "retire" there for it to count, but it's not the case.

From IRS.gov:

>Distributions made to you after you separated from service with your employer if the separation occurred in or after the year you reached age 55