How to rasterize multiple objects seperately?

When combining graphic elements in an .ai file, these elements being large bitmap images (tif, psd, png,...), I regularly use rasterize to reduce these images -seperately- in size (and thus reducing file size) and thus make working with them a lot easier and faster.

However, when I try to rasterize multiple objects at once, these objects are always grouped in one big rasterized object. Is there a way they remain seperate objects?