Contacting every one within call (8)
I believe the answer is:
reaching
'contacting' is the definition.
('reach' can be a synonym of 'contact')
'every one within call' is the wordplay.
'every one' becomes 'each' (I've seen this before).
'within' is an insertion indicator.
'call' becomes 'ring' ('ring' can be a synonym of 'call').
'each' placed inside 'ring' is 'REACHING'.
(Other definitions for reaching that I've seen before include "Arriving at a destination or a goal" , "Arriving at, attaining" , "Contacting" , "Connecting" , "Arriving at a place" .)