Hi, I regularly get my cows to accept multiple calves---90% of the time I am successful, but occasionally, I have a cow who will flat out refuse to nurse any calf but her own.
You mentioned that the cow you want to use to feed the calves kicks your stanchion apart weekly and kicks off the inflations daily--do you use any kind of kickstop on her?
Sometimes it helps to use a kickstop, tie the cow to a stout post, and then introduce another calf. The cow can't do a whole lot to intimidate the calf, and may stop wanting to. I also tell my cows to knock it off, and this works a lot of the time, coupled with a hard stare, though when I have my back turned, the cow may revert to rejecting the calf.
Is the Jersey milking out completely? You don't usually get the cream til the end, so if she is holding up, you might be missing out. The cream ratio should improve through the lactation. With some of my fresh cows, I really don't get much cream. As they let down better, I get more. When the calf is weaned, I get it all.