ugcPost retrieve corresponding activity urn

Question

I'm trying to work with linkedin api to retrieve posts of my organization. There's a problem regarding ugcpost, i.e post with videos included.

I'm able to retrieve them using for example:

curl -X GET 'https://api.linkedin.com/v2/ugcPosts?q=authors&authors=List({my_organization})&sortBy=LAST_MODIFIED' \
-H 'Content-Type: application/json' \
-H 'Authorization: Bearer {token}' \
-H 'X-Restli-Protocol-Version: 2.0.0'

But in the response there's only the urn ugcPosts. How can i retrieve the urn for activity?

For share urn it's easy to call shares endpoint and get the activity. I can't find any similar here.

I know there's this question that summarize my problem: LinkedIn v2 API: How can a ugcPost-URN be converted to a share URN? Anyone know how to overcome this?

Thanks