Responsive Images with different image files

I am working on a project with severval content elements like teaser, sliders, carousel and so on. each of these elements has one image with three different images optimized for the viewport. I do not want to use automated cropping here, since there is also text in the image. So three separate images…
I made a ResponsiveImageMixin which perfectly solves this issue.

But now I have another content element which contains two images instead of just one and the mixin does not cover the second image. Is there any way to declare a mixin multiple times with different property names? Or is there a better way to solve this problem? (childNodes? custom property type?)