Clint,
Thanks for being so patient with me. It turns out when I thought I was jumping to the Main page
in reality what the code was doing was ending the conversation and then jumping back. And you're right, in that case the conversation is ended as it should be. I do have a link on each page that jumps back to the Main page without ending the current conversation. When I click that link, the conversation is not destroyed
and I get the result I expected. So, I guess the last few posts have been a non sequitur. Sorry for wasting your time.
With all that said, I think your approach of a new per-request flag for extending the conversation sounds like a good way to go.