daterange for comments

Hi, this is a great module! I was so happy as I found it, because I was very upset, that views were not able to expose the same filter twice.
Would it be possible to add a range for comments, too? So that the final search would look like this:

WHERE ... AND (node.created < xy OR comments.timestamp < xy) ...

I want to use it in combination with Views Fast Search. Just searching for a node-daterange does not give good results, as the nodes are very old, but comments are added repeatedly.

Any hint appreciated.