How to tell someone they are overstepping their mark - Tactfully - workplace related?

There are two teams. Team A has scientific backgrounds and are actively engaging the project. Team B have a cultural affiliation and they must oversee the work done on the project. Team B should not be ordering team B around. Both teams are integral. How can team A (i.e. the money) explain to team B that their co-oporation and knowledge is essential and wanted, but let team A do their job??? Help. x