Conditional Validation in Java

I am trying to do bean validation in a Object graph. Lets say I have two classes called Foo and Bar. They have @OneToOne relationship.

Foo.class

class Foo
{
    String a;
    String b;
    boolean c;

    @Valid
    Bar bar;
}

Bar.class

class Bar
{
    String i;
    String j;
    String k;
    String l;
}

I want to validate Both Foo and Bar but I want to do conditional validation on Bar depending on the value entered in Foo.class. Depending on the value of c in Foo.class, I want to validate the fields in Bar.class. If c is true, then I want to validate i and j. If c is false then I want to validate k and l.

Is there anyway I can do it?