In a relationship (5)
(Other definitions for together that I've seen before include "Well-balanced" , "as a group" , "In combination" , "United; touching" , "Concertedly" .)
'in a relationship' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for taken that I've seen before include "Removed, accepted" , "Kidnapped" , "Stolen; occupied" , "Removed (from a place)" , "Appropriated" .)