To Bake the Texture of Multiple Objects
Set up the texture-baking parameters of each object you want to bake. Do this one object at a time.
On the Render To Texture dialog
Objects To Bake rollout, change All Selected to All Prepared.
Click Render.
Textures are rendered for all the objects you previously set up.
Parent topic:
Workflow: Rendering to Texture (Texture Baking)