anti_group_set_target , but how to set the target's target ?...

[gorom]

<Action event="anti_group_set_target" senderName="#SetAsSender">
                    <Notifications>
                        <Message>LEFTCLICK</Message>
                    </Notifications>
                </Action>

that sets your target. Does anyone know the syntax to set your target to the target's target ?...

in pseudocode : anti_group_set_targets_target

but that , ofcourse, doesn't work

also , where can I find references to the anti_group_set options ?