I think it would be a good idea to create a space where everyone could share 3d objects prepared to insert as GP4 scenes.
Its time consuming creating every model from scratch and it would be a lot easier if we had a database with those kind of objects that are not in the original tracks - standing people for pits, different trees, buildings and so on...
I dont know how to organize it apart from each one creating links to their individual mediafire or whatever deposit banks.
Someone made a database worksheet for cars, mods, etc some years ago, its very useful but its a gigantic work.
Well, i leave here the suggestion...