Automating creation of single, smaller, pdf from multiple large pdfs

Each evening 20 - 60 publication pages are sent to my ftp site for various purposes. Accordingly they come in as very large files so that they can satisfy the printer but are then downsized for presentation on the web. At this point it is all very manual.

The process for the printer works fine but I am looking for a better solution than manual for creating a single document for the web and distribution via email.

I am looking for a process that will allow me to resize the individual pdfs to a much smaller size and then combine all into one document.

Can someone point me in the right direction.

Many thanks for any help.

Jim