Macho Russian guards sing together (6)
I believe the answer is:
chorus
'sing together' is the definition.
(I've seen this before)
'macho russian guards' is the wordplay.
'guards' says the answer is hidden in the clue.
'CHORUS' can be found hidden inside 'macho russian'.
(Other definitions for chorus that I've seen before include "Some chanting" , "Song's repeated part" , "Organized group of singers" , "People singing" , "Pipe up in unison" .)