That works, thank you very much! It was, as you pointed out, the jump>always>End of form for each group that I was missing.
There seems to be an artefact of the jump function (it being unable to jump to an adjacent question), in that when I create my first radio question with the choice of which group to jump to, I have to put an extra question between this radio question and the groups, so that the response from the first question can jump to the first group. The extra question is effectively invisible, so never answered, on the phone questionnaire. This is not a problem for the functioninng of the forms, but have I missed a trick?