One minister and another holding firm (6)
I believe the answer is:
deacon
'one minister' is the definition.
(I've seen this before)
'another holding firm' is the wordplay.
'another' becomes 'dean' (I am not sure about this - if you are sure you should believe this answer much more).
'holding' is an insertion indicator.
'firm' becomes 'co' (a firm is a company).
'dean' going around 'co' is 'DEACON'.
'and' acts as a link.
(Other definitions for deacon that I've seen before include "Junior minister" , "Ordained cleric" , "Church official - canoed (anag)" , "Cleric - canoed (anag)" , "Rank of clergy" .)