Depending on what your situation is, how about adding Gate/Comp rack to your to your drums maybe some reverb too?

Am I assuming right that this is a church choir or similar ensemble with drums?

You shouldn't have to work too hard for isolation as long as your drummer isn't beating the piss out of the drums.

Think about it - your overhead pair of mics should be picking up essentially what the audience hears. If those mics are picking up an abundance of drums, then your audience is hearing nothing but drums and very little ensemble.

Tell your drummer to play in a more appropriate style or maybe give him/her some wire brushes.

Cheers-

J.

I feel your pain. I'm doing church sound in a temporary setting on Sunday mornings. It's a school auditorium, and we have to set up and break down every time. The volume levels aren't extremely loud, but it IS a rock'n'roll band. Our drummer plays with the country singer, Winnona (Judd), during the week, than comes home on Sundays to play with the church band. He's used to playing mid- and large-sized venues, and is a hard-hitting dynamic player. When he comes in on Sundays, he's ready to rock the congregation. We have a set of Clearsonic panels ( we affectionately refer to these as the "sneeze-guards"!), but because Mike is set up right next to the choir risers (ugh!), I needed to get more isolation from his kit.
The first thing I did was to fabricate a hanging "sound blanket wall" around him. I used sound blankets available from Markertek (google them and get their free catalog, these are on page 333). I built an easy-to-assemble frame out of 2x4's and wingnuts to hang them from, and typically use one wall on the choir side and one behind hi, This lets him keep line-of-sight with the bass player and the others, but not the choir. This isn't an issue for us, but you do have to be cognizant of this.
The second thing to do is mic'ing the choir properly to minimize bleed. CUCCO here had a very good suggestion for me when I ran into this earlier this year. Instead of using these nice recording LDC recording mics, I replaced the pair with a pair of good ol' SM58s in an ORTF arrangement. This minimizes phase issues, and actually sounds better than the Equiteks did. I still get the drums in the choir mics, but to a much less degree, and what I DO get sounds better in the mix.
Anyway, these are some things to consider. Good luck!

Having recorded plenty of rock-and-roll gospel, I am one who also recommends SM57's/58's (really don't need 58's on choir) on the choir but not XY. You need spaceed SM57's on the choir and probably at least 4 or, more. Phase cancellation is really not a problem on the choir with multiple microphones, especially when doing rock-and-roll gospel. If people were really concerned about phase cancellation, why would anybody use more than a single microphone to make a recording? Right. So be reckless! It's fun.

Recklessly using multiple microphones
Ms. Remy Ann David

What I read is drums bleed into everything else. There is no way to stop that unless you totally enclose the drums. No vocal is going to be able to compete.

I am assuming that you are talking about recording services, otherwise you would be tracking in a real venue, or tracking drums apart from the other instruments/vocals.

If this is the case, you can do what the rest of us do in this situation...go V-Drums. It keeps the stage volume down. I made the band go all direct, no wedges, all in-ears, drums totally enclosed and then V-Drums, and guess what? I could get the overall volume down, because I wasn't competing with the ambient stage noise and roaring backline. I was also able to get more tone out of the Steinway, and the choir could be heard at 110dB SPL-A in the house.

Get the stage quiet and you gain headroom, control and tone.