[xiju]

Welcome to YT. I introduced 2 eight week old Yorkies to two Lhasa-Poos. One was 16 and the other was 9. I had no problems. However, I imagine it depends on how your Maltese gets along with other dogs. Also, with the Maltese having been the only dog for three years, the introduction would have to be supervised for a period of time until they were used to one another. In other words until the Maltese realized that yes, the puppy was there to stay. Best of luck with your decision.