Should jobs be split between sectors?

Hello, I have a project for which I would like to calculate the impact of 1,000 jobs. The company's implan sector is 449 (Architectural, engineering and related services). However, when the project will move forward, they will not only need engineers. Are the different positions included in any sector, or should I spread the jobs over several sectors even if they will be part of one company? Let's say 400 jobs will be admin and such and 600 will be engineering, should I use 449 sector for the total 1,000 or should I put 400 in 462 (office admin services) and 600 in 449 (Architectural, engineering and related services)? Thank you for your help!