Just take the BritishFactory from Battle of Britain in BF42 as an example. Includes pretty much all the code necessary for that.
And give the official tut a try:
http://mdt.planetbattlefield.gamespy.co ... stroy.shtmIt's more difficult than it should be, but think that BF42 never was planned to include destroyable buildings in the first place...and there are far worse things we have to mess with than that...
If you want to make it really fancy, you can expand that by including the use of armoreffects. In theory and with a shitload of code this would allow for dynamically destructible objects, including "crumbling"-effects.
Making the object crumble in the spot you hit it however would be even more difficult, but by splitting the object into multiple small PCOs (which then again can be bundled) even that would be possible.
Perfomance would be a whole other sheet, just throwing in my spontaneous thoughts