The project plan is in the hands of the project leader, but...
These and other questions are commonly asked in project-oriented companies. Each project leader is clearly responsible for his project. This responsibility should continue. Only the project business is not always predictable and you have to react quickly.
Therefore, in SmartProjectManager, many individual project plans can be combined into one whole plan and the dependencies regarding deadlines and resource utilization can be considered as a whole.
In this way, you always have full control over the whole portfolio and its resources.