public abstract without sharing MyUnsharingClass {
     // Some methods...
}

public SomeClass extends MyUnsharingClass {
     // Some methods...
}

public virtual inherited sharing MyInheritingClass {
     public void doSomething() {
        // Some code...
     }
}

public virtual without sharing AnotherClass extends MyInheritingClass {
   // This class might be empty for all I care right now.
}

public virtual inherited sharing MyInheritingClass2 {
     public virtual void doSomething() {
        // Some code...
     }
}

public virtual without sharing AnotherClass extends MyInheritingClass2 {
     public override void doSomething() {
        super.doSomething();
     }
}