For context: I'm using IDA to reverse engineer Gameboy code. I'm using this Gameboy loader to load files. The Gameboy has a 16 bit address space, where addresses $0-$3FFF always point to a fixed portion of ROM in the ROM image, called the home bank, whereas $4000-$7FFF points to a selectable ROM bank. The loader in question emulates this by mapping the 16-bit address space to a virtual memory space where each memory is in a separate segment.
So far, so good. When code in the home bank is calling code in one of the selectable banks, I press alt-R to choose a segment for the target. This is unavoidable since IDA can't know automatically which segment the target is in. However, since the home bank is fixed, I would like to set up IDA in such a way that it automatically understands that all jumps to the area $0-$3FFF area end up in segment 0, without needing to manually assign addresses. $0-$3FFF in the virtual memory space always unambiguously refers to $0-$3FFF in the linear memory space. Is this possible?