[vetvetdoug]

There is a mention of the discussion in To Appomattox by Burke Davis, Copyright 1959, page 352. Alexander, Longstreet, Mahone, and Col Walter Taylor present. Alexander gets the credit for the suggestion but all were there. It is inconceivable that only Alexander and Lee were aware of the discussion.

[X Fretensis]

As I read it, it was Alexander’s suggestion. In his memoirs, he mentions others at the meeting with Lee, but only discusses his suggestion and General Lee’s rebuttal.
Others present may have contributed to the conversation, but to my understanding, it was Alexander’s idea.