> I know this is a weird one
That's not weird at all. Rather clever. I can see that being pretty useful actually, if I was looking at data based on ip-addresses.
Answer: you can't do groupings like that out of the box with vanilla data that only has an "IP" field. Ignore Prangadj's examples. The quickest implementation is to change the data you're returning to include a field with the ranges you are grouping on. So instead of just returning a field with "IP", you would also return a field "IPRange" that would contain the text value you're grouping on (eg "184.108.40.206-220.127.116.11"). Then just tell RadGrid to group on the "IPRange" field.
The downside of doing it this way is you're sending extra data in each row that could easily be extrapolated from the remaining fields. That may or may not be important to you. If it is, your second option would be to perform the calculations on the fly after receiving it from the db, but before binding it to the grid.