… two more, ten in group and the others cut (6)
I believe the answer is:
sextet
'two more' is the definition.
The definition and answer can be both quantities as well as being singular nouns.
Maybe there's an association between them I don't understand?
'ten in group and the others cut' is the wordplay.
'ten' becomes 'x' (roman numeral).
'in' indicates putting letters inside.
'group' becomes 'set' (set is a kind of group).
'and the others' becomes 'te' (I am not sure about this - if you are sure you should believe this answer much more).
'cut' indicates putting letters inside (some letters have cut into others).
'x' inserted into 'set' is 'sext'.
'sext' enclosing 'te' is 'SEXTET'.
(Other definitions for sextet that I've seen before include "Chamber group (1)" , "Group of six instruments or voices" , "Piece for six" , "Group of six (X, not S)" , "Half-dozen in a group" .)