MaJoC: Some years ago I published an essay on the subject of your query: "Prosodic Resonance", under the name "F Juniper", in _Word Ways_ 10:3 (August 1977). "Assonance" is indeed the word for resemblance in the vowels. Of course, we already have "alliteration" for resemblance in initial consonant cluster, and I managed to scare up "consonance" or "rim rhyme" for resemblance in the initial and the final consonant clusters. For the remaining possibilities, I suggested "deliteration" (final consonant clusters only, e.g. "hit" & "bat") and "insonance" (initial consonant cluster & vowel, e.g. "bat" & "ban"). Poets have of course used these resemblances as well.

It is not hard to find octets of syllables of which each clashes completely with one of the others and bears a different resemblance to the other five. I have written a number of poems based on such octets. Here is one:

Through the years, we've grown used
to the truth-telling boor,
    so rejoice in the yeast
      and its white lies on beer --
in the bubble-borne boost
to the bedlam where you're
    a contented old beast
      in a Happy New Year.