RadGridView Grouping loads of data

[Paulius Putna]

I am using this blog post as my example for working with grid view and huge amounts of data, but I came across a problem with grouping.
Scenario is this:

1. I have 10 000 entries
2. Page size is 200
3. I group by, for example, City.
4. What I get from that is page of 200 cities and each of them can have unlimited amount of entries, meaning that data load can potentially be all 10 000 entries…which would mean that my application will time out as it is too much data.

Any solutions to this problem would be great, because I don't really want to disable grouping, since it is a requirement for the application, but I will be forced to if there is no other way.

Thanks,
Paulius