SAP Adapter question

Hello all,

We linked a SAP ECC 5.0 version with SAP Adapter 6.5.
In our SAP production and pre production environments, architecture includes one central instance and 2 application servers.
These 3 instances have different IP and we should have declared 3 Listeners and duplicated all listener notification to be able to listen all 3 instances.
We didn’t manage it wthout this duplication

Is it a good way to process ? … For us, it appears as a big constraint to duplicate our listener notifications (there is a lot).
We want to know if it is possible to declare only one listener per environment and thus only one listener notification linked with each inbound message