ORACLE CONSTRAINT HELP

I have two tables table A AND Table B.
Table is a fact table and can be modified by business only.
Nothing can be done to table A.

I need to insert data in table B but have to check with data in Table A.
I have to make sure that data being inserted to table B must exist in table A.OR else it should throw error.

table A

id name loc
1  DELL  Austin
2  HP    houston
3  Sony  Japan
 
Table B
id name  ship
1  dell  comp
1  dell  server
2  XXX   XXX
3  YYY   YYY

So if i try to insert in id column of table B which is not in id column of table A,then  it should throw error.
like if i try
insert into B values (5,ZZZ,ZZZ);
then i should get error saying cannot insert 5 in TABLE B column ID.

PS: I cannot use foreign key relation. The constraint is pretty much foreign key ..But cannot use forgeing key as we dont want hassle while deleting from TABLE A. or B.