How to Create Nuget custom commands?

I have used some nuget packages and its Installation/Uninstallation works fine in Dialog mode and package manager console mode.

I need to Implement the package installation in some conditions in console mode.

Normally I used that command to installation

PM>Install-Package mypackageMVC3.40

PM>Install-Package mypackageMVC3.45

Now I need to install some assemblies only from mypackage.

I would expect package manager console to look similar to the following

PM> Install-Package mypackage.Group1.Mvc

Successfully installed 'group11.dll'. Successfully installed 'group12.dll'. Successfully added 'group11.dll' to MvcApplication. Successfully added 'group12.dll' to MvcApplication.

PM> Install-Package mypackage.Group2.Mvc

Successfully installed 'group12.dll'. Successfully installed 'group12.dll'. Successfully added 'group12.dll' to MvcApplication. Successfully added 'group12.dll' to MvcApplication.

I need to Installation and Uninstallation like this command.

I think the custom command needs scripts I have searched about the .ps1 script file but contents is not clear so please explain the Custom command creation..

Thanks