Baking Ambient Occlusion: shall i unite all HP objects in scene, for proper shadows?

I have three main groups in my project:
Group 01. Personage body.
Group 02. Belt and bags.
Group 03. Weapons.

Every group contains several highpoly and lowpoly objects:
Group 01 includes boots, boot’s buckles, spurs, jeans, torso, gloves, etc.
Group 02 includes waist belt, shoulder belts, bags, ammo belts, etc.
Group 03 includes guns, cartridges, ammunition, etc.
All lowpoly objects unwrapped and ready for map baking.

I’m going to bake normal map and displacement map individually for each object in every group, and later join objects to get three groups again. It seems there is no problem in using this method, when we talk about normal map baking. Because normal maps and displacement maps doesn’t need to take into account other objects and their influence on overall lightng. As far as i know normal maps and displacement maps, only deal with geometry of one, certain object.

Now, correct me if i’m wrong, but ambient occlusion maps must take in account other objects in scene, and how other objects reflect light, if i want realistic AO and self-shadowing of whole personage with weapons, bags, clothes, and so on.

So, shall i join all three groups into one when baking AO map, and also create joined copy of highpoly mesh for this purpose? Or I can just bake AO from joined highpoly copy of whole personage?

P.S. Now, when i think it over, it seems obvious that for AO map baking i only need joined highpoly mesh of whole personage, with all clothes, belts and weapons. And it doesn’t matter how i split my lowpoly objects, because lowpoly only used to store info about lighting and shadows from highpoly. But, i will be grateful for any tip or advice. Because i may be terribly wrong, and i don’t want to waste any time.