Allow to pass group.id to the push query

**Is your feature request related to a problem? Please describe.**
Hi, I would like to process the "select" query on multiple consumers within the same group (for parallelization).

**Describe the solution you'd like**
Would be nice to pass "group.id" to the PUSH query.
For example:
```
SELECT * FROM WITH (group.id="my-group-id") userEvents EMIT CHANGES;
```

**Describe alternatives you've considered**
I thought of using `kafka-stream-api`, but to be honest it looks like an overhead just to split the jobs into multiple consumers.

**Additional context**
Running multiple observers creates a group-per-query. It makes the parallelization much harder while using push queries.

Thanks for your help!