rule "modify dt2 rule"
    salience 100
    enabled true
    ruleflow-group "group_a"
    lock-on-active true
    dialect "mvel"
    when
        dt1 : Dt1(a == 1)
        dt2 : Dt2( )
    then
        modify( dt2 ) {
            setT("YES")
        }
end


rule "b_1"
    salience 96
    enabled true
    ruleflow-group "group_b"
    lock-on-active true
    dialect "mvel"
    when
        dt1 : Dt1( )
        dt2 : Dt2( )
        eval(dt2.getT()=="YES")
    then
        System.out.println("");
end


rule "b_2"
    salience 95
    enabled true
    ruleflow-group "group_b"
    lock-on-active true
    dialect "mvel"
    when
        dt2 : Dt2(  )
        eval(dt2.getT()=="YES")
    then
        System.out.println("");
end

public class Dt1 implements java.io.Serializable{
    private java.lang.Integer a;
    private java.lang.Integer b;
    // seter  geter 
}

public class Dt2 implements java.io.Serializable{
  private String t;
    // seter  geter 
}