There is a argument 'all' to scan, which lets you scan all directions at once. It's not much harder to type 'scan all' than 'scan e'... So I don't really see why you need an alias to scan all rooms.

But on the other hand the requested feature is sort of unnecessary since it's not too hard to get the same result through substitutes. Wintin example:

#action {You scan %0.} {#var scandir $0}
#substite {*** Range %1 ***} {$scandir: (Range %1}}

Or something like that I'm not currently logged on so I don't know exactly how the scan syntax looks.