Lagre building modeling suggestion

Greetings, The project we are modeling is a huge one - a little more than 900 000 sq ft and it is not C&S. Up to third floor (including two basement and two above ground floors) all areas are connected. As of third floor, the building is split into three independent corpuses (independent also in respect to the HVAC systems). Modeling the project as a whole (following that the Baseline systems should be one for each floor - system 7) it will be rather slow due to the huge calculation volume imposed to the modeling software, especially when calculating all the 8760 hours, etc. The question is: Could we split the building into 4 parts - one for the common areas (up to 3th floor part,) and one for every corpus. The calculation results afterwards will be assembled in the Minimum Energy Performance Calculator. Following the above suggested approach we’ll minimize the eventual errors and software problem that might arise and at the same time we are complying the appendix G requirement of modeling system 7 (which is the project's system). Looking forward to your advice. Thanks.