Taming reverb in a big room -- not a studio

[longtails]

Hi all
I'm new. This question isn't actually about a studio, but a huge rehearsal hall -- I apologize if it's out of place. I've looked around a bit, but I'm not sure that I can figure out an answer to my question just from looking around, I'm hoping someone can weigh in with some insight.

Basically, my band and a couple others have just moved in to a new rehearsal space, but there's a problem. On the one hand, it's huge and the price is right, but on the other hand, it's huge and there is TONNES of reverb. It is almost impossible to actually play in. Sound is just crashing around everywhere.

The room is about 60' by 20+', and I think the ceilings are about 12' high (the place is out of town for me, so I can't easily measure at the moment or probably for a little while), concrete and brick throughout. It is all window along one side.

I was thinking of building some large L-shaped partition walls in the space to hopefully break up the reflections, but I have no idea if this will work. Some friends in the construction business offered materials and labor to do this, so the walls would probably be residential-style 2x4 construction with pink insulation and drywalled both sides.

I've included a rough sketchup drawing to illustrate the room and the walls I'm thinking of. The image shows two partitions, but there would probably be a third (three bands share the space).

***we do not need to soundproof the room from the rest of the building, nor acoustically treat it for recording -- we simply need to cut down reverb. any insight would be very, very appreciated!***