Extracting a named interface from a list

Hello,

I'm a junior programmer working in Delphi 2009.

I am trying to separate some dependencies in my code so that I can use some dummy objects for unit tests. The main concept is to have a list of interfaces that is populated with implementing classes. These are to be used by several other units.

I would like to be able to extract an interface from this list in the calling code. The caller knows the name of the interface that it requires and the name of the method that it requires. Do you know if this is possible please?

Thanks in advance