Prefix/suffix env name to buildroot output bins

Hi,

I'm using build environments to build multiple images for multiple devices and multiple archs. I store some custom files for single devices in the buildroot/files directory. All easy and cosy, awesome.

The only problem I have is the output bin directory: multiple devices using the same arch result in the same file names, but the images built contains different additional files.
I tried to change the output bin directory, but doing so I'll have 2 copies of the same packages, imagebuilder, sdk, and whatever else sharing the same arch.
I tried to change the "Release distribution" name in the "Version configuration options", but doing so results in some vars changed in /etc/os-release at run time.

Is there a way to append the env name ('cd buildroot/env' directory, then 'git branch') to the output files names?
If not, is there some configure option to append a custom string to the files names? Any key-value pair stored in .config would be ok, if it doesn't change anything else on the running filesystem...