I need to clearly distinguish between investments (this is approval, this proposal, this software, etc.). Is this possible, or does it work only in bulk (attach all files together)?
Thanks,
You can create separate lists for each item that requires an attachment, and then link these lists in the main table.
SharePoint does not support attachment metadata. I would suggest storing attachments in a document library (possibly with content types for approval, suggestions, software, etc.) using the search column of the related item in your list.
There are two options.
Custom code is another one.