Indian and Nepalese leaders hold brief amongst themselves (5,2)
I believe the answer is:
inter se
'amongst themselves' is the definition.
(Latin term)
'indian and nepalese leaders hold brief' is the wordplay.
I cannot quite understand how this works, but
'and' could be 'n' (common abbreviation for 'and') and 'n' is found in the answer.
'brief' could be 'terse' (synonyms) and 'terse' is found within the answer.
A single letter 'i' remains which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for inter se that I've seen is " How classicists may write among themselves".)