yes it is possible, just copy the url for one of the forum feeds and back out the ItemID parameter leaving the pageid and mid params
like if the url is "http://localhost/Forums/RSS.aspx?ItemID=1&mid=13&pageid=11"
change it like
"http://localhost/Forums/RSS.aspx?mid=13&pageid=11"
the ItemID represents the individual forums
Hope it helps,
Joe