Aggregating two 4G/3G data links from 2 different sims?

Having two 4G capable sims -from truely two different operators (no virtual carriers at all)- and a Dual Active sim phone (Zenfone 2 Laser), I want to do true load balancing with a 1 sim + 1 sim 4G/3G data links configuration. However, all I can find when googling is about Dual-Carrier -or Dual-Band (HSDPA++, LTE)-, which is clearly not what I'm trying to do since it's just combining two same operator frequencies to boost speeds. The approach is like the "speedify" tool, but instead of mixing 4G and WiFi, I only want to mix the 3G/4G sims. So, the question is: Do someone know how to achieve that on Android ? By the way, is this automatically managed in Android, or is it driver/kernel/modem (e.g. Qualcomm X10, X12 hardware/firmware, etc) dependant or do I have to enable something manually ? Any information about that is ok too :) If possible, the best scenario would be having twice the Dual-Band enabled. This means a Dual Carrier + Dual Carrier configuration, for a total of 4 bands from two totally different operators.