I don't know how to pull it off, but last week our trainer was basically begging us to take in another GSD.  Supposed to meet it in a week or so. 

"its so unlike other GSDs and is so unbelievably friendly, just like yours, and with how well you have done with her, you were our first thought. we don't want to see it sent to the shelter, even if you just foster it a while", Not its "fault". The owner didn't know, but apparently their older dog in the family does not like other dogs. Sort of the situation i have here, tho we have worked around it. And fostering is a scam. its just a back-door route to adoption.  i have 'foster-failed" twice now with cats. lol. tells you something if they even have a term for it.