Combine 2 animations

Hello, i had made 2 projects. Part I animation and part II animation. They both are in FLA format. I want to combine the 2 animation together. But when i move the part II to part I animation, due to some of the symbol i made had a same name,

like symbol20 is a circle in part I, is a square in part II, and hence when i copy part II into part I, the part II animation symbol square changed to circle. And this is the main trouble while copying.

Do anyone know how or any program to copy my PART II animation.fla into PART I animation.fla without changing any data and sound in part II or PART I? thanks.