Not sure what "destroyed" would mean in this context. I read somewhere that a modern military unit is generally considered to be destroyed if it sufferes greater than 20% casualties, although there was at least one U.S. Civil War unit that suffered 100% casualties (even the sergeant writing the report had been lightly wounded) while remaining functional.

Although far from conclusive, a google search found a computer-translated Russian wikipedia entry [https://en.wikipedia.org/wiki/5th_Guards_Motor_Rifle_Division] for the organizational history of a Soviet mechanized division. The article has a glaring lack of operational details on Afghanistan, which I think is particularly telling since it discusses the unit's destruction during the Barbarossa campaign of WWII quite openly. The article does note an overall total of 1135 KILLED in Afghanistan, against an overall total of 11,907 members successfully withdrawn. Assuming at least a part of the withdrawn total were replacements for original unit members and also assuming the usual ratio of wounded to killed (about 3-4 to 1 in conventional war, as high as 6-7 to 1 in an insurgency), I'd say that there probably WAS a point where one or another of the 5th GMRD's component brigades was "virtually destroyed."    

[NOTE: You've probably already seen this:  file:///C:/Users/Owner/Downloads/ADA529242%20(1).pdf]