We have about 1000 E1 users that are using O365 MFA. We dont want them to receive MFA prompts when in office, only when on an external network. This can be done by the trusted IPs section in the O365 portal but it is limited to 50 IP ranges (why 50?). We have over 300 address ranges that we want to add. Is there a way to do this without giving the users EMS E3 licenses and using conditional access?