I could really use some expert help. I’ve got this formula that will filter out just screen resolutions for mobile devices within Google Analytics, now I want to build a regex that filters screen resolutions  for ranges 600-800 and then another that filers 1024-1600 and another for 1600+ This way it will allow me to group my visitors and see stats based on these groups.

Here’s the regexp I have that already works which filters just these resolutions:
320x200
0x430
120x220
/(^[1-2]?[0-9]?[0-9]|^3[0-1][0-9]|^320)x([1-3]?[0-9]?[0-9]$|4[0-7][0-9]$|480$)/

here's some sample input data that I'm trying to filter for the rest of the resolutions
1024x1600
1920x1200
1600x1200
1920x1024
1600x1024
1400x1024
1024x1024
800x1024
640x400
600x400
600x240
320x200
0x430
120x220