Hi
This is what Resource Modelling is all about and no I would never suggest you use Excel to do Resource Modelling. You must use a planning tool such as MS Project.
You don't have to edit the tasks themselves to level resources what you can do is just use the predecessor column to create the relevant links. If you can let me have your email address I will send you a sample plan indicating this. For some reason I am unable to attach a zip file to this post (my email is otpm@blueyonder.co.uk)
Hope this helps. If not get back to me with further detail and I will see what I can do to help.
Good luck.
Tony(OTPM)