Yes, group by ID, Credit and SIGN(Amount)

>I have a table with this structure and values:
>ID Amount Credit
>1 15 .F.
>1 10 .F.
>2 10 .F.
>2 -5 .T.
>2 5 .T.
>2 25 .F.
>
>I would like to Sum the Amount column and group by ID and Credit. But I want to show negative and positive values separately, so I also want to group on negative or positive.
>
>I would like this as a result: Is this possible?
>ID Amount Credit
>1 25 F
>2 35 F
>2 -5 T
>2 5 T
>
>