Hello， I only care yellow color loss， how to improve my loss function

[whk6688]

hello, there are six different colors in my pair picture， but I only care yellow color's change, how to improve my loss function.
following is my script:
python train.py --name house_512p --label_nc 0 --no_instance --gpu_ids 0 --nThreads 4 --niter 50 --niter_decay 100 --resize_or_crop none

thanks.