Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
So do these team members actually have knowledge they could be sharing? I think you need to figure that out before asking how to get them to provide said knowledge.
That's like making upgrades to a house one is renting. You either need to restore the property back to the way you got it when you leave/give it back or your upgrades stay with the property.