We have cases where one stream (S1) is as follows:
row,key1,value1
1,1/A/X/Y/B/D,123345

...and second stream (S2):
row,key2
1,1/A
2,1/A/X
3,1/A/B/D

...and would like result stream (S3) to be (matching key1 to key2 fields):
key1, key2,value1
1/A/X/Y/B/D,1/A,12345
1/A/X/Y/B/D,1/A/X,12345

Essentially this is a matching similar to Java 'contains' or 'startsWith'; or plain-old regex.
We are trying to avoid DB look-ups if possible. StreamLookup would be perfect if it supported 'regex' matching instead of only == type matching. Haven't tried FuzzyMatching yet. Any suggestions will be appreciated.