This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
There is no way to make a class visible only to derived classes in the same package.
'protected' makes a class visible to derived classes, but also derived classes in other packages, and it also makes the class visible to other classes (that are not derived from the class) in the same package.