Variation of Multisite for school campuses

Thought I’d post in multisite as it’s in that region, but I’m actually looking for solution to a slightly different scenario that I don’t think Multisite addresses.

I’m looking to redevelop the web presence for a couple of schools that are merging into a single federation. Currently they have independent very similar sites (theme and content). Both run WordPress at separate domains on separate servers.

Moving forward the separate schools are no longer going to be refried to as schools and are going to be known and referred to as ‘Campus A’ and ‘Campus B’ under the rebranded umbrella federation (e.g. schoolfederation.com). There will be quite a bit of content common to both campuses (curriculum, policies etc) and then content specific to each Campus (blog posts, events, calendar, staff etc).

To make the management of ‘both sites’ or ‘the site’ more efficient, Id like to be able to have an approach where the common content pages exist at schoolfederation.com/page_here/ but the content specific to each campus exists at subdomains campusX.schoolfederation.com

Additionally I’d like to be able to publish some content only once if it applies to both campuses, hence the idea of having common content appear at schoolfederation.com as opposed to publishing content to both campus sites/subdomains. This would save mud time and I think we only have a single admin within the school who is going to manage/edit the content.

I have come across the hub/spoke approach described ‘ here‘ but I’m not sure if this is the best way to go about it. The latter does not cater for featured images, authors and custom fields (and therefore true custom post type support).

Wonder if any of you have experience of a similar set up and maybe an alternative proposal or suggestion about the best way to set this scenario up.