I mixed the album of my former death metal band a few years ago...drums weren't recorded to a click and I got ALL the
drums on one stereo file, tracked with 5 mics...it was the horror.
What actually worked quite well was the following process:
I copied the track a few times, tried to get the bassdrum right on one and did loads of surgical cuts on that track so
you won't hear alot of the other stuff, did the same for the snare, the toms and all the cymbals, than I mixed those
tracks together with the original track and than eqd and compressed it altogether.
Still sounded like shit, but compared to the origianl track it was gold, in your case it's probably harder because all of
the toms are in a similar frequency area and so on, but it might work, besides that, some surgical cuts and some
compression should work quite well.
What kind of music is it? For fast death metal where the toms should be really precise and stuff it's probably hard,
for stoner rock...I wouldn't bother at all.