Load Balance Office 365 URLs

Hi Sameer, which version of BIG-IP are you running? In v11.3 and above, the SSL Forward Proxy feature will let you decrypt outbound SSL traffic, assuming you have installed a cert/key from a trusted internal CA on your LTM, and configured it in the SSL Forward Proxy options of the client SSL profile on the outbound virtual server. There's a beta iApp for this here: https://devcentral.f5.com/wiki/iApp.SSL-forward-proxy-with-web-acceleration-iApp-template.ashx

That iApp only allows for one pool of routers, so you would still need to add an iRule to forward the Office 365 traffic to a different pool. Something like:

when HTTP_REQUEST {
    if { [string tolower [HTTP::uri]] contains "microsoftonline" } {
        pool o365_pool
    }
}