Material Parameter Collections in material instance? How to promote to parameter?

Hi I have allot of sequencer tracks with turning on and off objects its not realistic to make a separate material with a transparent fade for each with **Material Parameter Collections, **so if could just put seperate MPC in the material instance at least would only have to make a few material collections. How can I make a parameter for this in material instance when i right click on the node it does not let me make a parameter for it , need it exposed?/controllable selectable as in which one to use in the material instance. Thanks!!!