Presumably, whichever field this is, you are an expert in it, and the editors respect you as such. So, if you hate the paper, and think it should not be published, I don't see the downside to telling this to all editors who ask. If you don't hate the paper, but think it is not quite Annals-worthy, you can just say in your review "I don't think this paper is suitable for Annals of Math, but I think it would be well-placed in the Albanian Journal of Irreproducible Results (or whatever)." Once you have an internally consistent view on the paper, again, I see no problem with communicating this to editors, and you are doing the author a favor, since the second review is very quick.
In fact, in many cases, editors work on multiple journals, and I have heard of papers being submitted to (eg) Annals, and then being accepted to (eg) the Albanian Journal of IR. Presumably, this makes the author reasonably happy, since the paper actually appears somewhere in finite time.