Regular Expression Extractor in loop

[Standa Černý]

Hi!
I need to extract values from response several times and number of
repeating depend on value FEATURECOUNT which I'm also extracting from
answer. I looking for lowest xmin, ymin, and for highest xmax and ymax
values from all the features. Could I use While Controller or some other
logic element to loop through and find min a max values?

Response looks like this:
var XMLResponse='
<?xml version="1.0" encoding="UTF-8"?>
<ARCXML version="1.1">
<RESPONSE>
<FEATURES>
 <FEATURE>
  <ENVELOPE minx="-730691,1005" miny="-1053035,2805" maxx="-730650,23"
maxy="-1052997,1"/>
  <FIELDS ... />
 </FEATURE>
 <FEATURE>
  <ENVELOPE minx="-730670,6305" miny="-1053018,2505" maxx="-730649,71"
maxy="-1052995,55"/>
  <FIELDS ... />
 </FEATURE>
 <FEATURE>
  <ENVELOPE minx="-730678,26" miny="-1053020,5905" maxx="-730662,96"
maxy="-1053002,6095"/>
  <FIELDS ..
 </FEATURE>
 <FEATURECOUNT count="3" hasmore="false" />
</FEATURES>
</RESPONSE>
</ARCXML>...

And it could have as much as 25 features.