Dressed as group matured (8)
I believe the answer is:
bandaged
'dressed' is the definition.
(bandaging is a kind of dressing)
'group matured' is the wordplay.
'group' becomes 'band' (band can mean a group of people).
'matured' becomes 'aged' ('age' can be a synonym of 'mature').
'band'+'aged'='BANDAGED'
'as' is the link.
(Other definitions for bandaged that I've seen before include "Dressed" , "patched up?" , "strapped up" .)