Using region source to create texture ?

i need help, i am new on texturing.

I am doing a little mobile game.
I want to minimize the number of textures in my final package.

I want to create one texture with all button in the same source.
I am wondering if i can create a new texture with a another texture with a region source (same as sprite process).

button content.PNG
button content.PNG

thanks a lot in advance :slight_smile: