Wish I could help you....I had an issue with my 2 yorkies girls and our HUGE Maine Coon.....McKenzi was here long before we got the girls...If we showed him any affection for if he meowed (Sadie...first yorkie) would attack him!!
Now....a 22lb cat and a 5 lb dog ...sadie(my alpha girl)would NOT back down....then a year later we got Lillie...she picked up the same habit from her big sister...there were a few times I had to put McKenzi in the bedroom for the dogs safety...as he got older he slept alot but, when he would move around they were right there and ready to jump on him! I had to watch them constantly...He could have really hurt them badly...I would say NO! clap my hands...smack a rolled up newspaper on my leg...nothing seemed to work...I would take them out of the situation then they would be fine...Sadly McKenzi took his journey over Rainbow Bridge the Monday before Thanksgiving..I truly believe the girls knew how sick he was...they would just sit and look at him...never tried to jump or chase him...all this being said...we will never bring another cat into our home as long as we have yorkies....never had this kind of issue before with any of my dogs...