Functional problem with sort in threaded order

At the company where I just started, they communicate via some BBS written 
in PHP. It does what it's designed to do but people would rather use 
mailinglists. i.e., they prefer push instead of pull. The BBS system 
displayed the messages with an indent that shows the thread information. a 
reply is indented by an amount that lets you see the scheme.

I showed them how much I liked mj2 but the response was that when we 
display the archives in threaded order, there is no depth to the display.

My proposal is that if you simply add a couple of spaces or the correct 
number of leading plus signs to the subject, the problem would be solved.

Can this be done? Is it easy?

-- 
Time flies like the wind. Fruit flies like a banana. Stranger things have  .0.
happened but none stranger than this. Does your driver's license say Organ ..0
Donor?Black holes are where God divided by zero. Listen to me! We are all- 000
individuals! What if this weren't a hypothetical question?
steveo at syslang.net