get conten from main site categories in multisite

I have a Multisite installation where subsites can show information from the mainsite to their own site. All the information (categories, posts etc.) gets posted in the mainblog. Users with a subsite then have the possibility to select certain posts from the mainsite to show own their own site. Subsites can’t add their own posts and categories. So far this is working (back-end wise…).

The current setup is:

Mainsite: https://www.example.com/
Subsite 1: https://www.example.com/subsite1
Subsite 2: https://www.example.com/subsite2
etc.
On a subsite, the navigation shows the categories which the user has selected their posts from. When a user clicks on a category it needs to get routed to (for example): https://www.example.com/subsite1/category/thecategoryname

This is allready happening, however I get a 404 page. Which is in fact abvious because the category doesn’t exists on the subsite. But, I want to switch to the mainsite, get the content from the category and return to the current site to show that content before the 404 gets called…

Does anyone know how I can achieve this?

I’m not shure if this makes any sense… If not, please ask me the info you need to know. I really want to solve this issue.

Thanks!!

With kind regards,

Douwe