Multi user file transfer

[Sue]

I'm currently working on a ASP project that I have a ASP form for user to randomly pick up 5 files out of 67, my program will pick up the five files, concatenate them, zip it up and upload it to a web server for user to download. Now my problem is: if in case that two user access the form at same time, user A pick five big files, it takes long time to concatenate them, user B pick five small files, so my code will do B's files faster than doing A's files and then will send out B's result for A to download, what way I may use so that each of user can get the files they want?
Thank you very much for your help!!

[Sue]

Dave: Thank you for replying. Sorry, I didn't make it very clear: user should be able to choose any number of files equal or uder 5. If I keep all of them in web server, that going to be thousand of files. Is there anyother way, that I can delete the file after user download it? Somebody mentioned HTTP transfer to me, anyboday know what is it? How it works? Thanks again!!