Modifying add_time of a file in API

Hi all,

I am bulk import of files from a different CRM system to Pipedrive. For these files I have the original date when these were added to the old CRM system. I am trying to reflect this data in the “files” field under an organization, right now all files are just bundled under the date that I have uploaded them. The problem is that some organization have about a 100 files, which results in all files being bundled under one, making it very disorganized. See an example herer:

I have tried adding “add_time” in the body of my Post request, but this is not supported. Also tried a patch request, but no luck there. The docs mention nothing about the add_time parameter, and searching the forum also does not result in anything specifcially for the files endpoint.

Any help much appreciated!