Material Parameter Collection Colour Fading

Dear creators,

I am currently working on a personal archviz projecrt, learning many things along the way and hopefully finishing with a cool project to show for it. Modelling and texturing is coming along well, and now is the time to implement some interactions. One of these gives me trouble:

The project is comprised of a huge main hall, which has one main colour. I would like to be able to change this smoothly using a button, fading to the next colors as its pressed, and stopping when it is released.

I used a material parameter collection to be able to change the color of many items in the scene at once. This way i am able to change the colour of many materials at the same time while only having to adress that one MPC.

However, so far i have only been able to implement an abrupt, non-fading colorchange. I tried to look up tutorials for fading colours into eachother, but when i tried to mimick it, replacing the normal color node with a MPC node that has the colour in it, it hasn’t worked for me. I’m very new to the scripting so i’m not able to figure out why it doesn’t work or what i should change to make it work.

So, can anyone help me by telling me the best way to do this, and maybe help me on my way? Any help would be appreciated.