Virtual join works by doing these steps for my case. it does not solve 100% of my issue.
1. data table A with column name "UNIQUE". Some of the rows are with same content under "UNIQUE", meaning UNIQUE is not unique in data table A. Save data table A.
2. Tables -> split as data table B with UNIQUE as column & tick "Save Scripts to Source table". Set UNIQUE as link ID. Save data table B.
3. Set "UNIQUE" as link reference and ticked "Select" under link reference properties in data table A.
4. when i select the content under UNIQUE in data table A, the UNIQUE in data table B will be highlighted.
what i would like is the UNIQUE in data table A is highlighted when i move row to row in UNIQUE in data table B.