Different HDRI for 2 different objects or similiar idea. Tweet

[unnamed7]

Hi,

i'am searching for an idea how to light 2 different objects with two different hdri maps (or something similiar)
1. hdri for metal
2. hdri for diamond

What have i tried:
1. main hdri + some area lights for diamond. Tried light pass'es, including / excluding lights from metal but result is not great.
Diamond is just not bright enough.

2. main hdri and sphere with inverted normals, emmissive material on it with its own hdri, light pass only to brighten diamond excluded from metal.
This works pretty good, but if i dont drop opacity to 0 of material i can see reflections of second hdri on metal.

Ugly reflections in metal part of ring.

If i drop it to 0, diamond looks flat/ugly as it only reflects really simple metal hdri environment + light emmision from sphere material(?)

yet metal part looks as i would like it to look

Maybe i can somehow exclude reflections of that sphere on metal ?

3. also tried to figure out osl and rayswitching but i think its a bit to complicated for me now - maybe thats the way ?
Maybe i can disabled sphere reflection in metal part with some rayswitch magic ?

Any pointers would be greatly appreciated, as i struggled for weeks now with this jewellry renders

[boxfx]

Would also like to know if this is possible, currently we are doing separate renders and compositing afterwards

[unnamed7]

i tought about that, but i really want to avoid separate renders.
Right now i can automate evertyhing with python script that switches stones, metal colors and ring crown.
Internal octane comp is all i need, dont even have to touch photoshop / ae - just run script and collect houndreds ready renders after some time for my clients ecommerce sites.
Yet some of them just want that unrealistic scene - pure white background with shadow/ground reflection, very bright diamond(or with some blueish tint), smooth metal reflections.
Seems kinda hard to achieve with one go