Here’s my process for range brass:
I inspect every case, and separate range pick ups by caliber. While I do this, I set aside any cases with crimped primers. I do this all in one flow, using my Harvey deprimer. I wind up with brass that is in groups of the same caliber, with GI versus commercial of each type further separated.
Doing it this way, I can easily identify whether cases with military headstamps are actually once fired, since the different resistance from the primer crimp is easily detectable.
For most purposes, commercial brass of the same caliber all goes together, though I often separate out nickel plated brass to use in special loadings.
To me, just about all usable .38 Special or .357 Magnum brass is interchangable, as is just about all commercial 9mm brass. 5.56 commercial brass is usually interchangable, though I pay attention for known headstamps - PMP from South Africa (still turning up some places) is thicker and needs a different powder charge; IMG and some others have a tendency for smallish flash holes, etc.
I consider LC brass to be LC brass, pretty much regardless of headstamp year, and the same goes for WCC brass. I haven’t (that I know of) come across any 5.56 “WMA” brass (from Winchester’s Oxford, MS plant), though I have found plenty of 9mm from there.