how to connect 3 elastix server to pfsense

[marksantos]

Hello!
I have a little stupid question, but i'm really stucked.

i have 3 elastix server connected to the switch. my problem is many ip's have dual ip with internet on client pc. so the pc client encounter a conflict ip. how can i connect three elastix server to a single ip via lan ip of psense

Here my network set up, without firewall.