Boasts about daughter to large groups of people (6)
I believe the answer is:
crowds
'large groups of people' is the definition.
'boasts about daughter' is the wordplay.
'boasts' becomes 'crows' (crowing is a kind of boasting).
'about' means one lot of letters goes inside another.
'daughter' becomes 'd'.
'crows' placed around 'd' is 'CROWDS'.
'to' is the link.
(Other definitions for crowds that I've seen before include "huge turnout?" , "Hosts" , "Hordes" , "Large numbers of people" , "Presses" .)