Multiple Users

I recently purchased 20 licenses (total of 120 eBooks) from RSMeans all registered under a single username email address and password to be shared by my company's 40 engineers and cost estimators.  RSMeans eBooks require Adobe Digital Editional (ADE) to be read.  Several engineers have now used the same email addres,  username and password to download ADE onto there device / computer.  But every time one person logs in and downloads an eBook, multiple eBooks appear on everyone else's library, along with additional and random partial / blank icons.  When those icons are deleted, different, appearantly random eBooks are deleted off of each of the other users' libraries.  How can this be managed?