backup node schedule?

Hi Pro's

I would like to create a schedule or script that start all my NDMP jobs one after each other.
I have around sixty jobs to start and I have six drives but only want four of the drives to be used at the same time (due I need the other two to be able to run restore and other backup jobs)

Is it possible to always have four jobs running? ex.. if four jobs are running and one of the job gets finished I would like an other job to start?
And is it possible to get some mail notification when any of my backups process finish?

My jobs I run looks like this:

backup node filer.company.com /company_vol0 mgmtclass=company_10_years toc=yes mode=full
backup node filer.company.com /company_vol1 mgmtclass=company_10_years toc=yes mode=full
backup node filer.company.com /company_vol2 mgmtclass=company_10_years toc=yes mode=full
backup node filer.company.com /company_vol3 mgmtclass=company_10_years toc=yes mode=full
etc...
(I have sixty of these jobs)