Exec is normally used for quitting the current script and going to a new system process (which can also be a perl script). System will run a second process and wait while it completes.

But what you want is to use or require your other scripts. But I would write those other scripts as subroutine libraries callable by the main script (as opposed to standalone scripts). And unless they are very long scripts, you might just want to put all your subroutines in the same file, it will make maintainence that much easier.