I would think that your close proximity to the bub would cause your body to produce hormones and be in tune with the new bub so you would produce the milk needed... just like when a group of women are regularly in each others company and their cycles end up being the same (hope that made sense)

I have also read (on an ABA website I think) that in some countries where there is a lot of farming work that they pair up women who have babies about the same age and one woman will work one day while the will feed both babies and the next day they swap.


So I definitely agree it is doable, sorry I can only give you anadotal evidence...