Working with those people with aim to be getting better (2,3,4)
I believe the answer is:
on the mend
'be getting better' is the definition.
(I've seen this before)
'working with those people with aim' is the wordplay.
'working' becomes 'on'.
'with' means one lot of letters go next to another.
'those people' becomes 'them' (I've seen this before).
'with' is a charade indicator (letters next to each other).
'aim' becomes 'end' (I've seen this before).
'on'+'them'+'end'='ON THE MEND'
'to' acts as a link.
(Other definitions for on the mend that I've seen before include "Becoming better in health", "Improving in health", "Regaining health", "Informally getting better, improving after illness or accident", "undergoing recovery?".)