append to items depending on prior item

[M. Clift]

Hi Alex,

I'm just gonna say thankyou for your time and effort. I hope that I've left
you and Peter with some hair : )
I can more fully appreciate now that I do not perhaps describe my
requirements as clear as I think that I do. You, however, have managed to
divine my needs, and both you and Peter have highlighted the fact that
perhaps I hadn't thought the problem through well enough in the first place
before I posted.

Anyway, bottom line is that this code will do what I wanted : )

All the best,

Malcolm