[HELP] BATMAN Adv mesh configuration with 2 instances

Does it makes sense to run 2 batman adv interface where one is used to run local mesh ( 40 nodes arppox ) and the second one to connect multiple local mesh.(second interface of batman will only run on few of the local mesh nodes from all the local mesh nodes)
If this is a bad idea what should I do and if not how do I do it?

(By following openwrt I create local mesh... I don't understand how to connect multiple local mesh)