I'm trying to work out if it's possible, with the extended XBetza notation, to allow capture as normal, but allow swapping with only friendly pieces that aren't the same as the swapping piece. As an example, for a Bishop I have mudBcB, which allows capturing as normal, and swapping with any friendly piece, but that also allows swapping with another friendly Bishop, which I don't want to allow. Any help appreciated.
I'm trying to work out if it's possible, with the extended XBetza notation, to allow capture as normal, but allow swapping with only friendly pieces that aren't the same as the swapping piece. As an example, for a Bishop I have mudBcB, which allows capturing as normal, and swapping with any friendly piece, but that also allows swapping with another friendly Bishop, which I don't want to allow. Any help appreciated.