I was just thinking about the same thing. I would like to use Orbot or Invisible as my default VPN but have some connections go through another VPN and then I wish I could run ReThinkDNS on top of that to filter things how I want.
It's not possible because even with custom coding to have multiple settings, GOS is build on AOSP and so any updates would make the custom coding problematic likely.
Really, the best thing to do is beg the ReThink DNS owner for even more custom settings so there can be multiple connections for VPN like this.
Since the maker of that program possibly visits this website, and I'm not to proud to beg, here it goes:
Please celzero, please! I'm begging you! Incorporate these features for us!
Pleeeeaaaase!!!!? ππππππππ¦Άπ¦Ά
π