the same thing happened to me, i had meeko and teeka and they were bonded, so i bought another because i always wanted a blue one,and meeko and teeka would always leave her out or if she would come around they would peck her, so a couple of days later i purchased another one "male" and another cage and put them together and now they are happy it just seems that all four of them tweet and tweet to each other like they want to be together lol, but also be careful with haveing 2 females and a male because they will fight over the male! if your going to have them in the same cage together i would suggest haveing a equal amount of sexes, 2 females and 2 males, because according to your pic it looks as though pretty bird and diamond are male and female and you say her in your post about the new one, if i were you ide get another male and let the two new ones bond, try putting a peice of millet in the cage maybe it will help them to bond over food, you know all eating at the same time. i really didnt give mine enough time to see if they would bond just the 3 of them because i was afraid of the females fighting so i hurried and bought the other male. anyway i hope some of this helps, good luck!!!!