Wind Load on Multiple Parapets

[waytsh]

I apologize if this had been discussed already but I was unable to find any threads. I am curious how others would handle a situation where you would have multiple parapets down the length of a building instead of just two (windward and leeward). In my situation I have multiple cooling towers with walls extending several feet above the roof line of the building resulting in what would essentially be eight parapets. Since the walls of the cooling towers are restrained by the roof of the building I am designing the roof bracing for the extra wind picked up by these walls. I am treating them as parapets for the purposes of calculating the wind loads. The question I am struggling with is how many of the "parapets" to treat as windward and how many to treat as leeward. My initial thought was to treat the first one as windward and the remaining as windward. Your thoughts?