introducing dogs question

Question
hi. I have a 1.5 yro chihauhau that is very timid but not aggressive (princess). My boyfriend has a 1 yr old chi and a 2.5 yro rotweiler. His dogs are great together. I am moving in and have been trying to introduce the 3. I started intro. the 2 chi's and his dog is younger and appears to just bully my dog. The rot really doesn't mind her but if he even gets close, his buddy gets mad (growls). The 2 chi's are female and the rot is male. We thought maybe a new femal chi would chill out the tough girl chi. Does gender play a huge role. How do i get his chi to stop bullying my dog. they haven't gotten super aggressive but his chi races after her or steps onto my dogs back and my dog cowers or hides in her bag. outside his house they seem better, but i want my dog to have a friend not constantly be scared. his chi insists on sleeping in my chi's bed and taking her toys--simplitically she's a gangster bully! help! i plan on moving in next month. what should i do? hold off on the new pup?

Answer
This is a tough problem and I can't promise success.  Gender is a huge factor, and 2 females is the worst combination.  Spay them if both aren't already.  It is no cure all, but otherwise, you may never solve the problem.  If he is neutered, it may make him less of a prize to compete for.

Obedience train them.  Failing to do so is a common mistake with small dogs.  The key to most behavior problems is approaching things using the dog's natural instincts.  Dogs see all the people and dogs in the household as a pack with each having their own rank in the pack and a top dog.  Life is much easier if the 2 legged pack members outrank the 4 legged ones.  You can learn to play the role of top dog by reading some books or going to a good obedience class. A good obedience class or book is about you being top dog, not about rewarding standard commands with a treat. Start at http://www.dogsbestfriend.com/  For more on being top dog, see http://www.dogbreedinfo.com./topdogrules.htm  If you are clearly established as the top female, then they are competing for the lesser prize of second place.  

It is too late to introduce them on neutral ground, but I wonder how important that is.  Meet her bullying with a sharp ''Ah, ah, ah!'' and redirect her.  Giving her a blast in the face from a spray bottle should help too.  Adding a little vinegar or lemon juice makes in more effective.