If all else fails, you can try the newspaper microfilm at your local library. If the relay qualified to regionals, there's a chance their place and time would've ended up somewhere in a newspaper. It really doesn't take long to find information on microfilm if you know the date of the newspaper or can narrow it down to a couple days.
I spent about a month digging through my school's old track and field results via microfilm to construct a more accurate school record list, stadium record list, and a list of our all-time top 3 performers in each event. I am lucky to live in a place where my school can get meet coverage from 2 or more local papers as long as they received the results.