Need help with javascript script (2x same code, 2 different actions)

This should be an easy one, I am pretty new to javascript in general so any help would be appreciated.

This is the script/code I am using...
http://www.java-scripts.net/javascripts/Slide-Show-Script.phtml

What I want to be able to do is have TWO or THREE different slideshows on the same page... each controlling their own images. I tried changing up the names of the variables for a second instance but didn't have much luck. The javascript "next" button for the second one was controlling the first, etc. I also tried renaming the goprevious/gonext functions to different names without much luck. I have no problems setting up a single gallery per page, but having more than one is giving me troubles.

Code on page for first gallery / site i want to implement it on:
http://www.tcsrailroadconsulting.com/alan/TCS/passenger.html

I just want to put another gallery for the other companies listed... to give you an idea of exactly what I want. I'm very new to javascript so a better understanding on how to complete this task would be helpful.

Thanks in advance...

after taking a closer look, I think I just need to change the original image name.. I was changing the src for the image but not the name itself, and I think that is what was causing the problem.... i'll post back if I still need help.