Question Fragment shader outputting multiple colours to multiple render targets in URP

Hello, I'm looking for some advice on the following:

I have some opaque objects to render with a specific material, but I also want them to output some info from that material that I can use for post processing later in the pipeline.

If I output multiple colours using:

struct f2a { float4 col0 : COLOR0; float4 col1 : COLOR1; };

How can I access this info later? Is it possible to tell the DrawOpaqueObjects stage to output to an additional target, or do I need to use a custom render feature? I'm a bit apprehensive about using a render feature because then I would be rendering my opaque objects twice.

I'm using Unity version 2021.2.7f1