t="Bef." width="4em"/>
                                    <p:column headerText="Tra." width="4em"/>
                                    <p:column headerText="Aft." width="4em"/>

                                    <p:column headerText="Bef." width="4em"/>
                                    <p:column headerText="Tra." width="4em"/>
                                    <p:column headerText="Aft." width="4em"/>
                                </p:row>
                            </p:columnGroup>

           