SQL & PL/SQL :: Select Query To Return Parent Rows?

I need to get the super set(parent) record from a relational table. Following is the structure of the table,

create table relation (data_field1 number(20),data_field2 number(20),data_field3 number(20),

primary key (data_field1,data_field2,data_field3) );
insert into relation (data_field1, data_field2, data_field3) values (-10,123,334);
insert into relation (data_field1, data_field2, data_field3) values (200,123,334);
insert into relation (data_field1, data_field2, data_field3) values (300,123,334);
insert into relation (data_field1, data_field2, data_field3) values (400,123,334);

[code].....

Here '-10' will be considered as parent(super set) for all other values. If i have records like below,

-10 200 300
100 200 300
123 200 300
521 201 300

Output should only contain two rows. A super set row and other distinct row(second column value is not equivalent to super set).