Query defining in wrkqry -> selecting records

Hi There,
Thank you for your help. I am completely new to this technology so I need help in basics.
Issue:-
eg: Account A,B,C,D
Balance in accounts:-
A -> -30
B -> 80
C -> -20
D -> 40
I need to consolidate data of A + B + D accounts into C account by either crediting or debiting the C account based on the balance of each account.
I need to do the same inside a query which is already created. So in select records i need to make sure that the records are consolidated and selected accordingly.

Please help me in defining the query to consolidate the data.