Having to confess in front of gathering (6)
I believe the answer is:
owning
'having' is the definition.
('own' can be a synonym of 'have')
'confess in front of gathering' is the wordplay.
'confess' becomes 'own' (I've seen this before).
'front of' indicates taking the first letters.
The initial letter of 'gathering' is 'g'.
'own'+'in'+'g'='OWNING'
'to' is the link.
(Other definitions for owning that I've seen before include "Being in possession or confessing" , "Possessing" , "Admitting" , "Conceding - possession" , "Possesing" .)