Is it possible to link form another page and tell this module to filter automatically?

For example: I have an Events module with 2 categories. I link from another page with the text "See all we have regarding Category #1!"  Can this link pass a filter request on to the module so that it is pre-filtered?

While I have your attention, I have one other question I can't find in the doco. (I'll post as a new thread if you prefer)

Is there a method for letting non-registered users enroll/register for events? The Enroll function seems to require login (Moderation is unchecked). We plan on using this to track webinars and do not want to force people to create IDs on the site, just redirect to a registration page.

I'm suspecting a Custom Field with a URL to the registration page is the way to go, but I thought I'd ask to be sure. Thanks!