option to move multiple rows at once

[michael-ts]

My table is displaying a tree layout (child nodes are indented in one of the columns). It would be nice if there was some way to specify ranges of rows that belong together, such that if the first row in a group is dragged, all rows in the group are dragged together. The groups could not be exclusive, because for instance if I have several levels of nesting, if I drag the top level it should also drag all the levels under it, but if I drag the second level it shouldn't drag the top level above it, just itself and the levels under it.