Why does SIL 2 want you two to "make up"? Is it affecting the rest of the family? Is it spoiling social events?
If not, I would just say to SIL2, you are both very different people and you think it best to keep apart. The other sister must just accept this.
Old sayings with a theme 2 ( continuing *nanna8*'s thread)
Last weekend, in Rutland, the first statue in Britain of the late Elizabeth II was unveiled.