Well.... If it was me, I'd put them together more and more every day. There might be a little nipping going on as they both figure out that the other isn't going to actually hurt them. As long as there's no real hurting going on, IMHO it's best to let them work it out. Put them together and stand back and watch. I bet that in no time, they'll work it out
Sapphire will figure out that Gwen doesn't want to play ALL the time, and Gwen will realize that Sapphire just wants to play. That's my theory anyway
I hope it works out, I hate to think of you having to keep them apart all the time
How stressful that would be!