Cross put in ground by religious group (9)
I believe the answer is:
intersect
'cross' is the definition.
('intersect' can be a synonym of 'cross')
'put in ground by religious group' is the wordplay.
'put in ground' becomes 'inter' (I've seen this in other clues).
'by' means one lot of letters go next to another.
'religious group' becomes 'sect' (I've seen this before).
'inter'+'sect'='INTERSECT'
(Other definitions for intersect that I've seen before include "Criss-cross" , "Divide into parts" , "making one cross" , "Cut across" , "Meet at a point" .)