Dimension3D's Poser File Editor I believe can also create inj/rem files.

As can his tool collection for Poser which is a bit cheaper. But PFE is pretty much an essential utility for any poser content creator.

https://www.renderosity.com/mod/bcs/poser-file-editor-3/62322/

https://www.renderosity.com/mod/bcs/tool-collection-for-poser/37406