Informed about keeping several colleges together (2,6)
I believe the answer is:
in unison
'together' is the definition.
(I've seen this in another clue)
'informed about keeping several colleges' is the wordplay.
'informed about' becomes 'in on' (as in being in on a deal).
'keeping' means one lot of letters goes inside another (some letters kept inside).
'several colleges' becomes 'unis' (uni can be short for university).
'inon' going around 'unis' is 'IN UNISON'.
(Other definitions for in unison that I've seen before include "All speaking or singing as one" , "All speaking or singing at the same time" , "Simultaneously" , "All singing the same notes" , "All together at the same pitch" .)