I am using Drools 4.0. I have the sample rule for agenda-group with output.Hope it helps   you.

Regards
Sankar S

OUTPUT
rule1
rule4
rule3
rule2
rule2.1

RULE
package com.sample.agenda

rule "rule1" agenda-group "rulegroup1"  auto-focus true
  when
     eval(true)
   then
      System.out.println("rule1");
   end


rule "rule2" agenda-group "rulegroup2"
 salience  12
  when
     eval(true)
   then
      System.out.println("rule2");
   end


rule "rule2.1" agenda-group "rulegroup2"
 salience  10
  when
     eval(true)
   then
      System.out.println(" rule2.1");
   end
  
rule "rule3" agenda-group "rulegroup3"
  when
     eval(true)
   then
      System.out.println("rule3");
      drools.setFocus("rulegroup2");
   end
  
   rule "rule4" agenda-group "MAIN"
  when
     eval(true)
   then
      System.out.println("rule4");
      drools.setFocus("rulegroup3");
   end