In the case you would like to have the Users limited on their share, and you have more users groups, you might want to configure them as shown below.

In the case of the internal users on their template account you can set the Required Share FROM Domain to your domain, so all users who access the files from the same domain, can create shares to anybody, their limitation being only the one that they have to use the company registered domain email address.

In the case of the external users you can create a new user let's call it upload and set the below customizations for it. With these customizations, you can achieve that the given user(s) can send files, only to the users from your domain and after uploading the file, they are automatically redirected to the share function.

As you might have several external users connect on the same time, you should set up a HomeDirectory plugin for them, and like, that all the uploading external users can have their own folder to upload to. On the

For the files and Home Directories not to take up space on your machine, you can set up a Folder Monitor, to delete the Home Directory folders and their files, that are older as one day.(The files will remain on the server as they are transfered on the share link creation.)

For the external usesrs you can give a direct link to use for the login and upload, like:

https://domainname.com:portnumber/?u=upload&p=upload
Https://crushftp.com:80/?u=upload&p=upload