Multiple HDRIs at once

[e-s]

It would be great to be able to use multiple HDRIs at one time instead of having them override each other.

[bepeg4d]

Please consider that HDRIs can take a lot of VRAM space, so better to discharge them if not used.
You can use two HDRIs at the same time, one for Primary Environment for lighting, and a second une in Visible Environment for backplate, reflections, refraction.

ciao,
Beppe

[J.C]

It would be great to be able to use multiple HDRIs at one time instead of having them override each other.

It's already possible. You can use node editor to add more HDRI maps.