Duplication content management across a subdir based multisite where subsites are projects of the main site and naturally adopt some ideas and goals from it

[PabloCulebras]

Hi, I have the following problem and would like which would be the best solution for it:

I have a site codex21.gal that is actually part of a subdirectories based multisite (galike.net). It has a domain mapping setup, but it is hosted on a folder of galike.net multisite (galike.net/codex21).

My main site (galike.net) works as a frame-brand for a series of projects aimed to promote the cultural & natural heritage of a region in NW Spain through creative projects focused on the entertainment, tourism and educational areas. The projects themselves will be a concretion (put into practice) of the general views of the brand, that acts more like a company brand. CodeX21 is one of those projects, it has its own logo, etc, and is actually like a child brand, yet more focused on a particular theme. I don't want to hide that it makes part of the GALIKE brand (in fact, I am planning to add the Galike logo to it, and a link to the main site on the menu).

I will be making other projects, each of them with their own brand, hosted in subsites (subfolders) of galike.net multisites. Not all of them might have their own TLD mapped, some could simply be www.galike.net/projectname. The project codex21.gal subsite might become galike.net/codex21 if it would be better for SEO.

Now, the problem is that my subsite codex21.gal re-states some principles, concepts and goals that have been defined (in other words) in the main site. Thus, there are some ideas (such as my particular vision on the possibilities of sustainable exploitation of that heritage, concepts I have developed myself as "narrative tourism" "geographical map as a non lineal story" and so on) that need to be present here and there on the subsite, since it is also philosophy of the project. BUT it seems that Google can penalise overlapping content in subdirectories based multisites, since they can seem a collection of doorways to access the same product (*)

I have considered the possibility to substitute those overlapping ideas with links to the main page of the site, thought it seems unnatural from the user point of view to be brought off the page to read a piece of info that actually makes part of the project description (every other child project of Galike might have the same problem).

I have considered also taking the subsite codex21 out of the network and host it as a single site in other server, but the problem of duplicated content might persist, and anyway, I should link it to my brand Galike somewhere, because that's kind of the "production house" of it.

So which would be the best (white hat) strategy, from a SEO point of view, to arrange this brand-project philosophy overlapping?

(*) “All the same IP address — that’s really not a problem for us. It’s really common for sites to be on the same IP address. That’s kind of the way the internet works. A lot of CDNs (content delivery networks) use the same IP address as well for different sites, and that’s also perfectly fine.

I think the bigger issue that he might be running into is that all these sites are very similar. So, from our point of view, our algorithms might look at that and say “this is kind of a collection of doorway sites” — in that essentially they’re being funnelled toward the same product.

The content on the sites is probably very similar. Then, from our point of view, what might happen is we will say we’ll pick one of these pages and index that and show that in the search results. That might be one variation that we could look at. In practice that wouldn’t be so problematic because one of these sites would be showing up in the search results.

On the other hand, our algorithm might also be looking at this and saying this is clearly someone trying to overdo things with a collection of doorway sites and we’ll demote all of them.

So what I recommend doing here is really trying to take a step back and focus on fewer sites and making those really strong, and really good and unique. So that they have unique content, unique products that they’re selling. So then you don’t have this collection of a lot of different sites that are essentially doing the same thing.” (John Mueller, Senior Webmaster Trend Analyst at Google. https://www.youtube.com/watch?time_continue=1&v=kQIyk-2-wRg&feature=emb_logo)

[PabloCulebras]

Please, any answer to this?