Shared blog with cross site canonicals

I want to maintain only 1 blog and have it apply to multiple stores on my install

I want to be able to do cross site canonicals on sites b,c,d,etc to give authority to the designate 'main' blog site and select which sites share the 'main' blog or use their own store specific blog.

(info on cross site https://moz.com/blog/cross-domain-rel-canonical-seo-value-cross-posted-content )

Can alternatively be a 'share this post on other blog" option for each blog post with selection of which blog to share content to and how to manage cross site canonicals