fbclient.dll allows access to internal transactions created at multiple transaction
1. create two connection: cn1, cn2
2. start of single transaction1 (cn1)
3. start of multiple transaction (cn1 and cn2)
4. start of single transaction2 (cn1)
5. scan the handles at range (transaction1_handle, transaction2_handle). Exclude handle of multiple transaction
Obtained new handles can be used as separate transactions handles.