Force elements in same batch

In our game iphone game we're drawing fake shadows under about every object. Although most are defined static (can't move only destroyed) they aren't batched all together. This is probably done to prevent drawing order issues. But as with many shadows this results in easily 10 draw calls for the shadows alone it would be useful to be able to force them in one batch (and live with possible ordering issues). Is there a way to do this?

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First, make sure all your fake shadows use the same material. Next, 'move' all your fake shadows into the separate rendering layer (Render Queue) by specifying:

Tags {"Queue" = "Transparent-1" } in the shader

Explanation: Unity have to sort all transparent objects by distance instead of sorting them by material. If you have different materials on transparent objects in your frame, then chance of them being batched decreases. By putting them into the separate rendering layer you tell Unity to sort them independently of other transparent objects - maximizing batching.