One step at a time. Get AB talking to ASL. You should be able to see the traffic from ASL to AB.
This is an ASL <-> DMR document. The concepts are the same. It's old (needs updating) so toy will see toDMR etc but the concept is the same.
You:
ASL <-> AB <-> MB <-> P25Gateway

Document
<ASL <-> AB <-> MB

<https://dvswitch.groups.io/g/allstarlink/files/ASL%20to%20DMR%20Bridge.pdf>