MultiPreloader problem

Hi,

I have index.swf (with preloader). On that SWF, there are two buttons.
Clicking the first loads external SWF, second button loads another SWF
on MC called mainMovie.

These two external SWF’s loads another external SWF (which loads pictures).

I hope you are with me so far.

I need ONE preloader to load every external SWF in ONE “preloader bar” and on click
to show without waiting.

Example:

first SWF = 12 KB
second SWF = 8 KB
third SWF = 7 KB
etc…

I need preloader to calculate how much bytes (or kbytes) has all SWF’s
together (in my case it’s 27 KB), and first to preload every SWF and
then to show entire site ready for use without waiting.

Anyone?