Pass record ID without using URL

I've asked this question on Adobe's forum, but surprisingly, I've not had any response... but plenty of views, so I thought I'd see if the old faithful community comes up trumps! I just need some idea on how to approach the following.

I need to pass a record ID when a user clicks a link, but I don't want to pass it via the URL. I can't figure out how to do so.

I have built a forum, and the forum users want to be able to quote a post and the respective replies. So, just like this forum, you have an original post, and then you have a repeating region of numerous replies below. So, what I need to do is enable the page to identify the unipue ID of the clicked record to quote from others that might also be available on the page, but without passing a URL variable, I can't figure out how to do it.

I would like to be able to set a session variable, but I don't know how to acheive this via a link so that I am passing the correct record ID.

Does naybody know how I can do it?

If possible, I don't want to use a URL variable for security reasons.

Thanks.