AFAIK arp entries represent port to mac address mappings in the TCAM table. The entries are used by switches to efficiently route frames based on the mac address mappings instead of having to broadcast the entire frame to all devices in the collison domain. Thus creating several collision domains.
If you wanted to broadcast the frame to all given mac addresses on a network, you could make do with just a hub instead of using a switch. Using one arp address for an entire network I dont think would be possible as layer two devices have to be identified using their unique layer two addresses for them to be able to decode the frame and pass it on for higher layers to decode them. If you do want to send a frame across to all devices on the segment, just address it to the mac address of all 1's.
Really doesnt make sense to me though :)
Then again Im a noob so dont take my word for it :D
