Rewrite problems

Hi - I cant seem to get my rewrites working.  Say I have this:

http://blah.blahdomain.com/folder1

and want anything to the above (such as http://blah.blahdomain.com/folder1/default.aspx or default1.aspx 

to be redirected to

http://blah.blahdomain.com/folder2 

such that http://blah.blahdomain.com/folder1/default1.aspx goes tohttp://blah.blahdomain.com/folder2/default`.aspx.

Is that possible?

Thanks

Craig