I saw on the Blender docs that you can use an emitter’s time ipo to make particles look like they’re being “absorbed”. Problem is, I can’t get it to do it. If I make the time ipo’s curve after baking, nothing happens, if I bake it after making the curve, the particles don’t move at all! (they behave as if all the speeds were set at 0)
I believe the post below will tell you all you need to know - it appears to be broken.
Best of Luck!