I have magazine of 80+ pages which i have completely designed with multiple files as you would do in any magazine design and i thought in the end i would just combine all the files into one BOOK format and publish online. But to my misery that option doesn't work with online publishing. Imagine tomorrow the magazine needs to give live for an event and now i have to create a new single file and copy paste all the pages into the new file and keep checking if all the interactive features are working fine. Thanks Folks at Indesign for making my life difficult with the supposedly cool "Online Publishing" feature of Indesign. honestly it sucks that guys at Indesign team havnt thought of this basic feature! :(