Do cocker spaniels get along well with other dogs?

ok so in my house we have lily, a 2 year old pure bred cocker spaniel, peaches, a 6 month old tea cup chiuaua and daisy, a 11 year old lab/husky mix... they all get along pretty well but we are looking into getting another cocker spaniel, we are wondering if lily would have trouble adjusting to another similar dog... like would their be an issue over whos the best cocker spaniel between the two of them?