[LTT]

dopus AnyPath\AnyFile
^ Running Directory Opus this way will make it open AnyPath and select AnyFile.

So, in EmEditor’s [External Tools], just add an entry for your Directory Opus. And [Arguments] is just “$(Path)”.
This will make Directory Opus handle the current file opened in EmEditor.

Will you give it a try and tell me if this is what you want?