I’ve only come across your blog recently, but I think I like your thinking.
To imply that we cherish mutual objectives is to deny the irreconciable differences and conflict that exist in many staffrooms (if your school is lucky enough to have one).
I understand Graham Wegner’s earlier comment about the Venn diagrams but I think that many of the more established community have shut up shop in terms of looking outside their circle, and now we only have concentric circles in operation.