Grids between spaces

[Lowitle]

Hi, 

I wanna ask you how I can make a connection between spaces airflow using grids located on doors or walls using revit.

Thanks,

Lowitle.

[Lowitle]

Maybe I used a wrong word with "grid". English is not my native language, sorry for issues. When I said grid I wanna say a "diffusser" that is not connected to any duct, a "difusser" placed on a wall or door.

Like that:
http://www.tienda.grupoincera.com/img/p/1868-2001-thickbox.jpg

or that:

http://img.archiexpo.es/images_ae/photo-g/rejilla-ventilacion-ajustable-67557-4936765.jpg

I hope you understand my question and try to give me an answer or the word you use to say "grid" correctly :-P. Thanks all.

Lowitle.