What is the best way to let user download multiple files?

[hinkeltje]

Ok, I have a environment where different users in different usergroups are uploading there training results.
Now I have the trainer, and he wants to download all the results per group at once, not file per file.

So if there are 10 users in a usergroup and they all have uploaded there training results, the trainer wants to press one button preferably to download all 10 documents.

I have been thinking and browsing for about an hour but I can't seem te set my mind to the right solution.
Can someone please help me what the best way is to programm this?

Thanks

[egami]

write a routine to zip up the files and download it.

[hinkeltje]

And have you any idea how to do this?

[tkdbb84]

http://php.net/manual/en/function.exec.php