Yes, with the use of multicast.
The servers will join a multicast group and the workstation will send a packet to the multicast group instead of unicast directly to the servers.
You need an application that supports multicast for this to work.
An application residing on both the workstation and the servers.
There isn't any feature available in the routers to duplicate a packet.
For entry level information on Multicast, this wiki should help http://en.wikipedia.org/wiki/Multicast
The problem is that one side I cant change anything, this side aways send a packet to one IP ( I was think about the router) and that equipament will send to the 4 servers or if the workstation send a packet to server 1, the "router" catch the packet and send to the others server too
I don't think a firewall can do this either. Replication of packets is something that is generally avoided.
Best bet would be some kinda of load balancer but replication is not their primary function either.
No, firewall is more limited than the router in term of IP Application services.
The closest thing a router can do is SLB (Server Load Balancing).
Please take a look at this document and let us know if it meets your needs.
Thanks again Edison, taking advantage of the opportunity, do you know if I can put a regular pci network interface on Pix 525? Which model?
Not recommended and unsupported by Cisco. You should order the proper replacement via your Cisco reseller.