Yes, it's actually very easy, though probably not obvious. It all has to do with the capture groups (the parentheses) in the input expression, which are reused in the output expression: '$1' goes with the first parentheses, '$2' goes with the second pair of parentheses, etc. (This works in the same way that capture groups work in regular expressions.) Assuming you keep the output expression the same, you can change the argument to the 'sequencingFrom(...)' method to this:
if you want the first capture group to include just the path, or to
if you want the first capture group to include the path AND the filename.
BTW, you might want to look at MODE-1013, which affects the XML sequencer. This has been fixed in trunk, and will be included in the next release (2.4).