FWIW, I’ve done what Derrek is suggesting before, and it does work, but only for single lines of text with the smaller text size. If you have multiple lines of the smaller text(s) in the text frame, then of course adding this larger space messes up the line leading of the lines above it. The ability to drag a guide into place would certainly be welcome here. If you just drag a line from elsewhere, you can see it does work for single lines of the smaller size text though.
