Molly is VERY jealous! I never knew it because when I adopted her I had two male greyhounds and one of the males kept everyone in line and Molly was part of the pack. We lost both Greys to cancer in one year and Molly was alone, so we adopted a 3 year old female beagle, Vazzy. Wow - girl fights! I thought it was Vazzy at first but then witnessed Molly go after vazzy with her hair up. We are more careful about giving them play toys together or things like Kong treats. I make sure they both know that I am boss and not one of them. Seems to help alot. It is definately workable which is what I was trying to say. Just introduce your new dog slowly and be sure to let your current beagle know she isn't being replaced.