Do well by leaders of community, integrating all locals (6)
I believe the answer is:
social
'do' is the definition.
(I've seen this before)
'well by leaders of community integrating all locals' is the wordplay.
'well' becomes 'so' (both can mean extremely).
'by' says to put letters next to each other.
'leaders of' indicates taking the first letters.
The initial letters of 'community integrating all locals' is 'cial'.
'so'+'cial'='SOCIAL'
(Other definitions for social that I've seen before include "Outgoing, extroverted" , "Liking companionship" , "Relating to human groups" , "Convivial - party" , "Gregarious or neighbourly" .)