Dynamic dropdown lists (chaining)

[JonasTheGamer]

Hi! I'm trying to achieve something, but I don't know if it's possible somehow.

I have a dashboard with data from multiple companies. Every company also has employee groups.

I would like to have the first dropdown allow me to select one or multiple companies (already managed to do that). On the second dropdown, I want the selected companies' employee groups to be there as options, and, once again, be able to select one or more.

I tried passing a query which has a parameter already to the first dropdown list, but then the options just keep loading.

If possible, how would I achieve this? Thanks in advance!