Commissions (noun) a task or matter entrusted to one as an agent for another.

https://www.merriam-webster.com/dictionary/commissions

The content in which the word is being used is, “… allowing them to work together and tackle big commissions that draw on all of their talents.” Article “Why Collaborate” page 2 of 2.

The definition in other words state that the word commissions is a big job or a given task. Lupton is explaining to us that sometimes we need teamwork to tackle big projects. Therefore, divide the work equally with others and based on individuals strength to get the work done at a quicker rate.