Either show your material setup, or i can upload material system i used to blend quixel textures, it has different methods for blending: noise textures, surface normal, height etc.
However i am not sure if my material setup is exactly what you need.
For you you should get some noise texture, use it as alpha and bled surface material with frost color using that noise as alpha.
And if you make single master material for all frosty surfaces, then make instanced materials out of it, you can drive that alpha noise amount from material collection, for all materials.