Russian -tsvo

From: Daniel J. Milton
Message: 41518
Date: 2005-10-22

A thread I was involved in on a non-lingustic group (of no
consequence, but
http://games.groups.yahoo.com/group/crossword-games-pro/message/61938
and previous postings with similar subject lines, if anyone is
curious) concerns the word 'zemstvo' "rural council".
This got me to wondering about the etymology of the suffix
'-tsvo', which "with a primarily abstract meaning, often designates
not only the abstract idea itself but also the group of people
associated with it (Townsend "Russsian Word-Formation")". I can't
find anything in references handy -- can someone enlighten me?
Russian has a good number of suffixes to form derivative words (more
than most I.-E. languages?). Can any generalizations be made as to
their origin?
Dan Milton