SuSefirewall2 with NAT for several servers.....

Hello friends, a question... Has somebody configured their SuSEfirewall2 with several servants that have addresses IP you publish each one?, How does the SuSEfirewall2 differentiate the packages that you/they go like destination to one or another servers if in the variable alone FW_FORWARD_MASQ the address source is placed, later the address private IP of the server inside your LAN? thank you, I hope they respond me..... please.