>i need to use preceding-sibling:: to jump from the 2nd a class tag up to the first a class tag
That's a bit like saying "I need to get from Berlin to Moscow by ferry". The two <a> elements aren't siblings, so you can't use preceding-sibling to get from one to the other.
Try
preceding::a[1], or
ancestor::table/preceding-sibling::table[1]//a
Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference