Bishop has one group to divide (6)
I believe the answer is:
bisect
'divide' is the definition.
(I've seen this before)
'bishop has one group' is the wordplay.
'bishop' becomes 'B' (chess abbreviation).
'has' means one lot of letters go next to another.
'one' becomes 'i' (Roman numeral).
'group' becomes 'sect' (I've seen this in other clues).
'b'+'i'+'sect'='BISECT'
'to' is the link.
(Other definitions for bisect that I've seen before include "cross" , "create schism?" , "Divide into two equal parts" , "Cut twenty [IN TWO]" , "Cut in half" .)