Unfortunately, no.
Without isolating the instruments from each other (either in space with partitions/separate rooms or in time like you're doing), you're going to end up with the instruments bleeding into each others' mics.
Now, that isn't necessarily a song killer.
Some bleed can be nice - it can help make everything sound like it's in the same space.
But in a garage, you're gonna have to be really careful about your mic placement and the phase issues you can create with multiple mics in a small place, along with the wash of ugly sounding small room ambiance you'll get from playing multiple loud instruments in a small untreated space. Listening to a faders up mix of the initial recordings you are doing (everything playing together and miced individually) should give you a good idea of what I'm talking about.
So, options:
1) keep doing what you're doing. It may be tedious and take a while, but if you're satisfied with the sound you're getting, there's no reason to change it. As you do it more often, you will get quicker and more efficient at it and figure out some tricks that work for you and shortcuts you can take.
2) Find a way to isolate the drums and/or treat your recording spaces.
Dunno if you've already acoustically treated your space, but it can help a lot with cutting down the overly-loud room reflections that will absolutely kill any clarity in your live recordings.
Drums being a particularly loud problem for me and mine, I've found that having the drums and drum mics in a room separate from the close-miced amps helps a lot with getting a usable drum sound that I can mix my close miced instruments with.
3) Check your monitoring chain and find a way to isolate it.
If you're monitoring through, say, computer speakers, there's just no way that you are going to be able to tell exactly what your mics are picking up.
Try and make sure that's up to snuff, but even if it isn't, try to make sure you get your recording medium (computer, 8-track, etc...) and monitors in a separate room from the room where you're tracking live.
The reasoning here is that, regardless of what the band sounds like in the room, the only thing you'll have to work with after you've recorded is what the mics themselves heard.
So it's of absolutely top priority that you hear what the mics are hearing (and only what they are hearing) before you ever hit the little red button.
Getting a fifty foot snake so I could sit in my room and have somebody else move mics in the living room around while the drummer played was one of the biggest improvements I was able to make in my home recorded sound quality. You really can hear things moving in and out of phase and hear how much room reflection vs. original sound a particular mic is picking up by getting yourself out of the room where the music is being played.
So, yeah, that's my thoughts on your situation, do with it what you will.
Have fun, good luck.
