Class 4 let's you upload a list of ANIs that you want to replace with. You can setup multiple ANI groups and specify the ANI group in egress trunk. Then, when terminating traffic via egress, Class 4 will replace the ANI for each calls that terminating via that vendor trunk.
Step 1: Go into Switch > Random ANI Group
Step 2: Define list of ANI Group
Step 3: Upload Numbers to your ANI Groups
Step 4: Associate the ANI Group to the vendor trunk