Pacific group about to enter long-distance races (6,2,7)
I believe the answer is:
league of nations
Here is my best explanation:
'pacific group' is the definition.
(I've seen this before)
'about to enter long-distance races' is the wordplay.
I cannot quite see how this works, but
'about' could be 'on' and 'on' is present in the answer.
'long' could be 'l' and 'l' is located in the answer.
This explanation may well be incorrect...
(Other definitions for league of nations that I've seen before include "Pacific group", "Old pacifists" and "international organisation".)