PDF Document Review and Commenting

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C#

PDF

itextsharp

I am planning to create comment functions on PDF files, which will be web based. Functions are,

Master user should be able to log in and upload a PDF file, and then assign numerous different users as reviewer.

As soon as master user add reviewer, no of layer on pdf document should be created & respective user can able to add comment on respective layer of same file.

All reviewer can able to see the comments on other reviewer layer but cannot edit, and able to write & edit comment on his layer only.

Master user can be able to edit comments on any reviewer.

Is there any open source tool to achieve above functionality?