which system are you proposing, and are you trying to avoid Fusion for any reason? (I see that Fusion has integrations with a number of file systems like box, dropbox, google docs/drive, sharepoint and probably others that I don't recognize, so I would think it would be possible to write a scenario that basically says for any file uploaded that satisfies a number of requirements, upload it to the system that you have a connection to.)
We have 3rd party web app which is linked to WF via Salesforce. Now we want to be able to push either through WF-SF-then 3rd party tool. or maybe directly from WF to 3rd party tool if thats an option. We are not looking at Fusion currently due to some other reasons; trying to understand if we can do it without it.