Is there any way to filter out or collapse the folders on the Iphone?

When we had a BES Server you could select which folders to sync. Unread messages would always appear in the main folder.
We then set rules so that messages we would need when out of the office would always be in the sync'ed folders. This helped reduce traffic and made the system very usable we don't need hundreds of low priority Emails all day long....

The way the folders appear on the I phone it can take a long time to find the folder where the important emails are being stored, Even by setting the push feature.

It would be great to be able to either collapse the tree or not display most of the folders.

Any suggestions would be of benefit....