Depth Buffer + Blending

I have a scene rendered using the depth buffer. I then need to render some transparent objects. All these transparent objects need to be blended together. These transparent objects need to depth test with the rest of the scene and not each other. Then other parts of the scene need to be drawn that can occlude these transparent objects.

Basically I need to put all the depth values for these transparent primitives into a seperate depth buffer and then merge that with the other depth buffer at the end.

Is there a way I can do this? Or another way to acheive the same affect. I do not have the option of sorted rendering.

I can use glDepthMask(false) but then the rest of the scene renders over these transparent primitives.