Wifi Calling Firewall Holes to Punch

Hey gang. We're setting up a unified wireless network for the students here, and to get around the issues with Nintendo and NAT we devoted a large chunk of public IP space to them. We're aware that this is causing issues with wifi calling on Verizon, TMo etc because it appears they initiate the SIP session inbound. Does anybody have a handy list of IP blocks and ports? T-Mobile had a decent page but other providers just said "open up 4500 and 500" and our ISO guys don't like that. Thanks if someone can help. John C. Lyden Manager of Network Infrastructure, Infrastructure Services Division of Information Resources & Technology, Rowan University