Joining more than 2 collections

[Zheng Lin Edwin Yeo]

Hi,

Is it possible to join more than 2 collections using one of the streaming
expressions (Eg: innerJoin)? If not, is there other ways we can do it?

Currently, I may need to join 3 or 4 collections together, and to output
selected fields from all these collections together.

I'm using Solr 6.4.2.

Regards,
Edwin