SQL2K - DRI problem

Table A is a 1-Many parent of table B
Table A is also a 1-Many parent of table C
Table B has an Fkey to Table C that can be null or have a value

I want to cascade delete from A to B, A to C, and C to B

SQL Server screams at me about "possible cyclical or recursive paths" - or something to that effect.
How can I accomplish this without having to do it all trigger based?

Thanks,