The past few months chloe will start fights with penny. Thats right! My 2.8 lb yorkie starts fights with my 90lb boxer. She is completely jealous if I ever touch penny(which is ridiculous because penny gets the least amount of attention becuase she doesnt conviently fit into our laps like the other 2 girls) and Chloe will actually start real fights with her but only over me, so luckily I always am there to break it up. Today however, Tinkerbell was in my lap on the couch and penny got up on the couch to lay next to me. My philosophy- the more the merrier. Well apparently Tink does not feel that way and did not want Penny sitting next to me and she started a low growl which initiated a very scary fight. My husband was sitting next to me with Chloe in his lap and of course chloe decided to join in the fight and my husband had to help me break it up, and somehow I ended up with a huge bruise on my arm when I was trying to break up the fight. I dont knwo what to do

. Poor Penny is getting less attention becuase Im trying to avoid these fights. My little girls are spolied rotten, and they always throw a fit when I try to give any attention to penny. I am the only person they fight over, they never start fights over food, toys or any other person, they only start fights over my attention/affection. I dont think Penny would ever really hurt the girls but of course it is scary that she is 10-20x bigger than them although she is the sweetest dog in the world. She never ever starts the fight but yet if the girls growl or try to attack her of course she isnt going to just sit there and take it. How and why did this start happening? What do I do to put an end to it? (and getting rid of a dog is NOT an option) I need help!