OK so in cisco land you can add an acl to the ip directed broadcas command, but this option does not appear in FTOS (Dell Networking OS 9)
if you enable ip directed broadcast on the vlan and then apply an ACL which allows only allowed hosts to talk to the broadcast address and then permits any other traffic would this achieve the same effect?
E.g. the following config
conf t ip access-list extended db10 permit udp host (WOLHostIP) any (BroadcastAddress) 0 permit udp host (WOLHost2IP) any (BroadcastAddress) 0 deny udp any (BroadcastAddress) 0 exit int vlan 10 ip directed-broadcast ip access-group db10 out implicit-permit exit