BIRT reprt - Expand collapse within the same report

Migrateduser

<p><span>Hello,<br>
I am a beginner in BIRT and I have to display a report as follows. I have a set of Events and each event has a set of versions. For example:<br><br>
Event 1 | Version 4 (last version)<br>
Event 1 | Version 3<br>
Event 1 | Version 2<br>
Event 1 | Version 1<br><br>
Event 2 | Version 3 (last version)<br>
Event 2 | Version 2<br>
Event 2 | Version 1<br><br>
Event 3 | Version 1 (last version)<br>
...<br><br>
I want to be able to display the last version in the report, and then have an expansion sign on the last version to expand and view the previous versions.<br><br>
Any idea how to achieve this? thanks a lot!</span></p>