Two partners in firm using prime locations exclusively for introductions (6)
I believe the answer is:
couple
'two' is the definition.
(couple is a kind of two)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for couple that I've seen before include "Married pair; two forces causing rotation" , "The pair to join together" , "Unite" , "Link together - say two married people" , "Duo, brace" .)