Hello
You should be able to write such wrapper by yourself.
Here is a sample of exposing .NET API to a plugin and calling it from a Delphi host: Need a Jumpstart with Delphi XE3 and .NET 2.0 DLL Assemblies Integration - #3 by antonk
Visual plugins can be used in a similar way, see the Delphi WPF sample.
It seems you would need to put the Groupdocs.Viewer component into a WinForms Visual plugin and to expose some of its API via plugin interface.
Regards