A single big space which include several functions.

Hi All, I'm now working on a project under LEED NC certification. The ground floor includes a conference room, offices, technical spaces, meeting rooms, and one big space, in which the following functions are located without any physical separations: - Two lobbies with reception desk - Corridors and circulation - Break area - Cafeteria The above-mentioned big space is served by 2 AHUs (which serve also other rooms). We pursue the verification according to ASHRAE 62.1:2007 and I'd like to understand which kind of space use we have to verify for this big space. Can we separate in different singles functional units, even if these are not physically separated? Thanks.