Is it possible to customize backup process?

Is it possible to add some custom pre/post hook-scripts for proxmox backup workflow?

You can specify a hook script with option "--script". This script is called at various phases of the backup process, with parameters accordingly set. You can find an example at "/usr/share/doc/vzdump/examples/hook-script.pl"
 
You can specify a hook script with option "--script". This script is called at various phases of the backup process, with parameters accordingly set. You can find an example at "/usr/share/doc/vzdump/examples/hook-script.pl"
Should I create in this case own cron job and delete all backup jobs from proxmox gui?
Is it possible to add for all jobs defined through proxmox gui this '--script' parameter? :)