Solution to re-use child class method within its siblings (ASP.NET/VB.NET)

I have 5 web forms which contains same user controls with different functionality. The current system follows MVP pattern. All these web forms inherited from a single base class (Please refer the following image.). Now, I have to disable each and every form individually for a certain condition which is common for all the forms. So, I wrote a method for one of the forms to disable each and every field in its user controls and it works fine. I can re-use this method for the rest of the web forms as they all contain the same set of user controls. Does anyone can suggest a suitable solution to re-use this method?