option to generate one bom per target framework

Instead of merging the dependencies of all target frameworks together, i'd like to see a way to generate multiple bom files, each one containing the dependencies for one target framework.

as explained in #1101, i currently need to execute the tool about fifty times in a loop to generate the boms i need.
This is rather problematic, especially when using --enable-github-licenses, since mostly the same licenses are fetched over and over again what costs time and quota.

any improvement in this direction would be greatly appreciated.
e.g. a --group-by option which would by default merge everything together, but could optionally bet set to group by target framework, target runtime, or both.