CallingPartyNumber-based routing with LRT

Hello.

 

I need the SBC to route calls based on CallingParty Number (From header) with using LRT in the following scenatrio:

 

Softswitch -->SBC----SA1

                         |

                       SA2

 

Say, there are two users, who generate calls from softswitch side towards SBC - 1234 and 5678. Both of them are calling to the same number,say, 1111. I need to route the call from 1234 to SA1 and the call from 5678 to SA2:

 

The call

From: 1234

To: 1111

has to go to SA1

 

The call

From: 5678

To:1111

has to go to SA2.

 

All the SBC parameters for the users on the SSW leg (realm, sip-interface...) are the same.

 

The ACLI configuration guide says that I can use multistage routing to check the From number, but it does not say how. I suppose that I should use LRT lookup with "key=FROM" parameter, but its logic is unclear for me...