You can maintain a table that stores table names that you want to load.
If you put a tHiveRow with a select from a table containing all the tables, you can first query that then pass it through a tFlowToIterate which will hook into the code you have developed so far.
In my example table tt1 has a list of the tables I want to query from.
select a from tt1
returns my list of tables, I pass that flow into a tFlowToIterate component then link via an iterate to the second tHiveInput (currently this is your first tHiveInput). All you need inside this query is the row+tableName that you have for the newly tHiveInput component.
"select * from " + row4.tableName
This will iteratively run that query on every table contained in the first table you query. At this point you can then hook the output into your tMap etc...This will only work if your tables have matching schemas