If you tick the "Let buyer edit quantity" box for a download product, the quantity ordered would multiply the Attempts you allow (without affecting the Hours limit) on the single link we issue to that buyer -- e.g., if you normally allow 5 Attempts within 120 Hours, a buyer ordering qty=100 of that item would receive one link valid for 500 Attempts within 120 Hours.
This help page explains how to customize the thank-you/download pages we generate for you, though bear in mind such customizations would appear for every buyer:
http://www.e-junkie.com/ej/help.custom.thankyou-page.htm
That said, bear in mind it's not even necessary to download a file multiple times to get multiple copies of that file. Users can freely copy or share any file on their computer, so they could just download the file once and share copies of it to 100 people. This is one reason we recommend providing ebooks in PDF format, which would allow you to set up our PDF Stamping feature to deter file sharing:
http://www.e-junkie.com/ej/selling-ebooks.htm
If you're selling a bulk purchase to a specific group of people, you may just want to take payment from the group leader independently of our system, and use the Send Free Download Link feature in your E-junkie Seller Admin to issue a link to the group leader, using their email address and something identifying the group as the First/Last Name. This also allows you to type a custom thank-you email to the recipient that would accompany the link, e.g. stating any special instructions or terms for the link you're providing. Free links sent in this manner would engage PDF Stamping if you'd set that up for the relevant product. The group leader would then download one master copy from this link and distribute it to the rest of the group on their own, by whatever means they wish (e.g. as printed copies, email attachments, DropBox, etc.).