@stefan-m2020 Yes, a script can do that. Here's a c# script that will do that:
 

using ScriptPortal.Vegas;

namespace Test_Script
{
    public class Class1
    {
        public Vegas myVegas;

        public void Main(Vegas vegas)
        {
            myVegas = vegas;

            Track myTrack = myVegas.Project.Tracks[0]; //zero is the first track

            TrackEvent prevEvent = null; //we will always extend the previous event to reach the current event

            foreach (TrackEvent evnt in myTrack.Events)
            {
                if (prevEvent != null) //if we have a previous event - the first time we will not
                {
                    prevEvent.Length = evnt.Start - prevEvent.Start; //extend it to reach the current event
                }
                prevEvent = evnt;//now the "current" event will become the "previous" event
            }
        }

    }
}

public class EntryPoint
{
    public void FromVegas(Vegas vegas)
    {
        Test_Script.Class1 test = new Test_Script.Class1();
        test.Main(vegas);
    }
}

If you haven't, you might also want to take a look at the scripting tutorials at www.jetdv.com. There's lots of good scripting information there as well.