VLANing my management network

I'm a complete neophyte at VLANS. I understand the basics, but I want more!

I have a network with a half dozen sub offices all on MPLS links.

I was wondering if it is possible to "span" a single subnet across all the sub-offices for my management network

site 1 - 172.22.28.x

site 2 - 172.22.40.x

site 3 - 172.22.48.x

site 4 - 172.22.56.x

Management vlan across all sites - 172.22.4.x

Or is bad/wrong/stupid?

Switches are Dell.