Union only if

Hi,

I have a pipeline where I need to send two sets of data streams union-ed

1. a one record stream with static values (not a header but kind of acts like a heads-up column for the remaining records)
2. a dynamic stream where the data is read from a data source.

However, I need to union them only if Stream #2 has data or otherwise send no data. I tried union and filter snap on snap.in.totalcount > 1 and it works fine when Stream #2 has no data but when Stream #2 has data it only sends data from Stream #2, as totalcount is calculated per row.

Any ideas?

Best,
Rajesh