No problem at all
On both sides of each IP Office line, set Fax Transport to G.711
Fax Finder is located at one location, use a short code to route calls to it, such as *23XXXX
At local site, *23XXXX / Dial / N / Line Group to FaxFinderIP
At each remote site, Short Code *23XXXX / Dial / *23N / Line Group for IP Office Line to home site