Yes, you can do this by packaging up your scripts together with a deploy.ps1 file using RGPublish
The documentation on adding powershell behaviour to your package is here
http://documentation.red-gate.com/displ ... ll+scripts
while information about creating packages with RGPublish is here
http://documentation.red-gate.com/displ ... n+packages
If you're updating four different databases, however, I'd recommend setting them up as four separate "steps" in the same project. That way you'll be able to see the logging and status of each database separately, while ensuring that all four get deployed together.