You can make a sequence of calls to leaf.table.List or leaf.table.Spread – NewLeaf will simply continue from where the last section ended, and will box around the whole table when you end the report, or run any non-table function such as leaf.Bump or leaf.Place.

If you want to run two tables back to back, you will need to complete the first one explicitly to get them boxed separately:

leaf.table.List mat1   © first table
leaf.table.Endgrid     © End table
leaf.table.List mat2
leaf.Close

It is harmless to run this function after every complete table, as it will do nothing unless a table is in progress.