It is a big implementation. you need to write code for this in simple following steps:
1. Create Apex: commandlink naming A t Z and bind each link with controller with passing value like A, B , c or 1, 2, 3....as per your understanding.
2. in controller you shuld use a dynamic Query where in where clause you need to apply A, B , C etc. value whatever you got from page on clicking on link.
and apply query and fetch result and update list used on A Pageblock Table.
It is a big implementation. you need to write code for this in simple following steps:
1. Create Apex: commandlink naming A t Z and bind each link with controller with passing value like A, B , c or 1, 2, 3....as per your understanding.
2. in controller you shuld use a dynamic Query where in where clause you need to apply A, B , C etc. value whatever you got from page on clicking on link.
and apply query and fetch result and update list used on A Pageblock Table.
3. Rereder Table section.