Assuming you have the following network structure.
Knowing the IP address of the WWW-Server, system A wants to send an IP packet. As I understand the destination MAC address has to be in the same system, so it should be MAC-R1-1 in this case. But how does system A find out this specific MAC address? I know it will send out an ARP request containing the IP-WWW and the switch will flood the local network with the given IP address. But how will R1 answer with its MAC address if the IP address in the ARP request ist IP-WWW rather than IP-R1-1?