I believe changes to the Eclipse Development Process require approval by the Eclipse Board, so if a rule change is necessary it would need to be proposed to the board. Whether or not an exception can be made for just the EE4J Working Group or if the change would need to apply to all Working Groups, I do not know.
If the rules germane to this issue cannot be changed, than instead of a rules change it could be considered a “courtesy” that is commonly extended to companies whose whose employee, elected as a committer, has ended their employment with that company. For example:
Project X has 10 committers with names (A, B, C ... J). Committer B worked for ACME Company when elected to a Specification Project. When Committer B is nominated they declare that although they are individual they also are an official representative of ACME Company. This proclamation is not binding in anyway, but is simply informative part of the nomination.
Committer B announces that they are leaving the ACME Company to become independent but will sign a new Committers Agreement as an Independent (or their new company will sign one) and will stay on Project X. The ACME Company makes a request that another employee, Ms. K, me nominated as a committer to Project X. The Project Lead, as a courtesy to the ACME Company, can choose to nominate Ms. K. The vote is taken according to normal Eclipse Development Handbook and Ms. K is either elected a committer or not.