I have installed BP and wanted to use Forums. However

I have installed BP and wanted to use Forums. However I want discussions to be threaded, and to show as indented lists to show replies under the relevant post, something like this...

Post 1
.... Reply 1.1
.... Reply 1.2
........Reply 1.2.1
.... Reply 1.3
........ Reply 1.3.1
........ Reply 1.3.2
........ Reply 1.3.3
Post 2
.... Reply 2.1
etc.

I don't think that this is possible?

If it isn't is there a forum, discussion board plug in that will allow this?

Thank you,

liz