Is this Network Structure feasible?

I have inherited 6 sites that I manage under 1 organization. All sites have a Sonicwall router. Site 1 is the datacenter where all services are hosted. All other sites make a PTP VPN connection back to the main office. Each site has its own lan subnet, a few 192.168/24 and a few 172.16/12. Is it possible to reconfigure the sites so that. Each VPN connection is made over a 172.16/32 address and have 10.x.0.0/16 vlans that span every site? If I had direct connections it would be cake, but I've never had to work with a scenario like this before. Here is a Packet Tracer diagram of what I'm trying to accomplish. https://imgur.com/s9JAr8q The top middle router is "The Internet"