Multi-Site with partly cross references

Hey there…
we use multi-site setup like here described: Using Kirby for multiple sites | Kirby CMS

So we use different subfolders for different domains but single folder for /site
Is there any solution to use content across those domains/subfolders?

for example: we have several subpages on my-site1.com/projects/, my-site2.com/projects/, my-site3.com/projects/, and so on… and we want to have a domain where all of these ar summarized.
like my-summarysite.com/projects/

for sure, we can use iframes or similar… but we want to use content inside kirby and render all together… for example to sort… and for pageination… and so on…
is this possible?