You likely have anger toward both people and so the anger toward the first one is spilling over to the second. ??In other words, you may have an accumulation of anger. ??First, please be aware of this if indeed this is the case. ??Then I recommend continuing to forgive the first person and persevere until the anger lessens. ??With lessened anger, and with the practice you now have in the process of forgiveness, you may find that forgiving the second person is easier than it was previously.