Indonesian Maritime Security Agency vessel KN Tanjung Datu, left, sails alongside U.S. Coast Guard Cutter Stratton during joint exercises in the Singapore Strait in August 2019. IMAGE CREDIT: PO1 LEVI READ, USCG
The Indo-Pacific Defense Forum reports,
Indonesia is reaching out to its South China Sea neighbors to foster harmony on maritime sovereignty issues and enhance cooperation among regional coast guards, analysts say. The nation engaged closely with Vietnam in late 2021 and plans to add five countries to the collaborative effort in 2022.
It appears Indonesia is working with its SE Asian neighbors to resolve their bilateral maritime territorial disputes based on UNCLOS and develop multi-lateral agreement.
This would allow the ASEAN nations to present a united front, to push back against China’s expansive claims. It might even lead to something like my proposed Combined Maritime Security Task Force.
Chuck Hill's CG Blog 
“China has long exploited the lack of common stance between ASEAN members. Finding unity among like-minded states, first and foremost, is necessary to outmanoeuvre Beijing’s “divide and conquer” approach.
“Resolving bilateral dispute and distrust are paramount. Smoothing out such internal misalignment is prerequisite to create any effective group, whether formally branded a coalition or not.”
https://www.lowyinstitute.org/the-interpreter/stiffening-asean-spine-south-china-sea