Will a kitten help my mean 1 1/2 year old cat?

We found a kitten that was 5 weeks old so we took him in and now hes 1 1/2 and he is so mean! Hes not really mean to us but whenever we have friends come over he attacks them and stalks them! He waits at the end of the hall for them to come out of a room so he can attack them!!! If we were to get a kitten would this help him? We have a 5 year old yorkie and they get along fine.. Sometimes they fight but when the cat was a kitten they would snuggle... not so much anymore.. What do you all think?