Which type of chart do I need?

[rnorman3]

Hi all, I'm new to visio.  I want to make a diagram of separate processes in one cloud type diagram, each process or task can have effects on other tasks.  For example two tasks might be "loading a truck" and "filling a tank", both require the use of the forklift, so they would possibly have an effect on each other if done simultaneously.  There would be other effects as well on other processes.  What type of visio diagram do I need for this?  Can visio make it such that if I select (click on) one of the processes it will highlight other effected processes? 
Thanks!