Not that I am aware of. SolidWorks macros work within the confines of the SolidWorks API. 3rd party addins are not a part of this as they really just macros in a compiled format. If you are aware of what the code is doing and how its done in the 3rd party addin you can create a macro to do just that. Are you looking to create a macro to do something that the addin does alone or are you attempting to add something to it? If you are adding to it then the best course is to add it to the original source.