What's the timeline between Resident Evil 2 & 3?

I'm a little confused of how the timeline goes on with Resident Evil 2 and Resident Evil 3. There is that secret in Resident Evil 2 where you can't use any ammo in the starting of the game until you reach the R.P.D. and that is where you unlock the zombie Brad Vickers. With that in mind, it made me curious to think that Jill Valentine came before Leon and Claire because of Brad Vickers appearing in Resident Evil 2, but it's also weird that Leon and Claire came before Jill in the game series. In Resident Evil 3 it does show Brad killed by Nemesis. In the cutscene, Brad enters wounded with portions of blood on his uniform. When you see Brad get thrown to ground and if you look close on his face, you'll see blood splattered all over his mouth or chin. When you fight Brad, you can see closely that there is blood surrounding his mouth and blood on his uniform. It is also speculated that Leon and Claire missed Jill by a moment when crossing over each others path. It could mean that when Jill barley left the R.P.D., Leon and Claire had just arrived. I do know that both stories were going on at the same time of both events, don't get me wrong. You can also view the zombie Brad Vickers as a hint of a sequel, but who would have guess that. Anyways, just leave me an opinion of which time and place took first. Thank you!