how can i create 2d sprite with two body parts (png files)?

hello, i'm trying to change the color of the suit from my game's hero, each suit will be in a exclusive color, but i want to avoid to create a suit for each color, i know how to change the color at runtime in easy way, but i have to split my player's sprites in two (the change color part: suit, and the fixed part: the rest of the body), i know how to do it in gimp.

my question comes when i open unity, how can i setup my sprites to create my player hero animations ?, each frame will be made of two sprite (the suit and the rest of the body), i know how to make aniamtions using a single frame made in the sprite editor, but i don't know how to create a single sprite from two images to use it a a frame key in the animation editor.

any help will be very useful.

thanks in advance for all the help.