I don't think it's a receiver feature but rather a firmware feature.
Only way I know to do some sort of search is to use the number pad on the remote to move to a channel name. Never needed to do a search and sort within E2 as I organize my my channels into bouquets using Dreamboxedit a feature only E2 receivers do well.
I also own an Amiko A3, had I know how sh*t it was going to be I would not have bought it.

This has a voice search feature which works rather well but which I have only ever used during playtime as once again I used Dreamboxedit to organize my my channels into bouquets and once done have no need for channel searching.
I guess the bottom line is that no such feature, as you describe, exists in E2 or I am not aware of any such. I suspect also that, I may already have covered the reason why not. So if it's a feature you value and feel you really need then perhaps you should consider using a different STB or taking it up with the E2 developers on their respective web sites.
Although we all do out best here to support images and related queries, especially our own home grown backups, we have no control over the base images nor do we have any say in what actually goes into them. In matters such as these we must therefore, remain impartial also but we do get visited by Development Team members from time to time who may be able to offer a better answer than I.
Hope this helps.