Drink with Kansas leaders in Kansas (6)
I believe the answer is:
topeka
'in kansas' is the definition.
('Topeka' is part of 'kansas')
'drink with kansas leaders' is the wordplay.
'drink' becomes 'tope' ('tope' can be a synonym of 'drink').
'with' says to put letters next to each other.
'kansas leaders' becomes 'ka' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'tope'+'ka'='TOPEKA'
Can you help me to learn more?
(Other definitions for topeka that I've seen before include "state capital" , "Kansas capital" , "Capital of 6" , "It stands on the Kansas River" , "Kansas City" .)