In theory split resources can happen. In practice it never has. The only real split is legacy IO/mem/vga. They are always supported on every chipset to date by a 'decode legacy range' bit.
So, in practice, the extensive capabilities of the resource stuff have not, as far as I know, every really been used. It always comes down to'contiguous memory range' 'contiguous prefmem range' 'contiguous IO range'
ron