Best place to put a proxy.pac

Our Internet Surfing Segregation (one of those  Secure Browser product/solution like
Menlo, Authentic8, Fireglass) recommended us to put a proxy.pac (Proxy Auto Config)
file in a webserver.

This proxy.pac will be pointed to by IE, Chrome, Firefox so that when users launch
these browsers, proxy.pac will launch this vendor's secure browsers when users
browse sites that are not in the 'whitelist' (ie trusted sites).

This is a Garrison product (garrison.com) : I thought of placing this proxy.pac file
in a corporate shared drive  so that in browsers, we can set in the proxy config
script as   file://c:/folder/proxy.pac  but IE11 doesn't support this file location
anymore (tho Chrome & Firefox still do).

Was advised by garrison that it's best to put in web server so that in IE11, can
specify as  http://...website.com/proxy.pac    but our corporate site is hosted in
a Cloud: don't think the Cloud provider (AWS) allows us to deposit a file in an
SaaS model.

What other ways other than setting up a webserver?  I do have a Solaris web
server that acts as  ClamAV depository (local mirror)  that runs httpd : what
are my best option?