Firstly, put VMware Workstation on autostart, and then use this small bash script to autostart your machines.
The script will parse your inventory file usually located in ~/.vmware/. It includes your config and paths to the .vmx-file that the script will use to start up the machine.
So change the INVENTORY variable to what your path is and just add put this line into your crontab
@reboot /home/USERNAME/scripts/vm-startup.sh