ITA Matrix (https://oldmatrix.itasoftware.com/) will let you explore options efficiently.

An example search:
- departing from "LAX, BUR, LGB" with advanced codes "AA,UA N"
- destination "BLR" with advanced codes "N AA,UA"
- dates outbound "07/12/2023" return "07/19/2023"
- cabin "Business class or higher"

This means you leave from any of LAX, Burbank or Long Beach, with the first flight marketed by either AA or UA ("AA,UA"), and then one flight on any carrier ("N"), going to Bangalore. On the way back the instructions say one flight on any carrier, followed by one flight on either AA or UA.

Currently, that shows me this in Business (D) for $8728:

UA8844 dep LAX 15:00 arr FRA 10:40 (+1)
LH754 dep FRA 13:05 arr BLR 01:25 (+2)
---
LH755 dep BLR 03:05 arr FRA 09:00
UA8845 dep FRA 10:30 arr LAX 13:00

You can of course refine that search lots of ways. E.g. changing the routing codes from "AA,UA N" to "AA,UA EK+" and from "N AA,UA" to "EK+ AA,UA" shows you routings like LAX-MUC-DXB-BLR... but those take longer, involve more changes of planes, and seem to clock in around $19K.

You can dive deep into the ITA matrix advanced codes here: https://www.travelcodex.com/advanced...nguage-in-ita/