Joining two buckets using GSI

How would i do a join on 2 different buckets with different indexes using secondary index?
i.e.

Bucket1
Document:
Key: blahblah
Value: {“index1”: “some uuid”, “field”: “blah”}

Bucket2
Document:
Key: someotherblah
Value: {“index2”: “some uuid”, “field”: “blah”, “field2”: “blah”, “other”: “things”}

create index idx1 on Bucket1(index1)
create index idx2 on Bucket2(index2, field2, other)

I want to join Bucket1 with Bucket 2 using Bucket1.index1 and Bucket2.index2

You need to use ANSI Joins in 5.5