qgis - Getting additional subbasin areas designated by points in river network？

I follow Watershed and Stream Network Delineation, and here's my workflow：

1. use Batch Point Generation to create batch points related to designated points(green dots)


2. Batch Subwatershed Delineation using these batch points

and I got this：

It looks great, but I still can't clip existing subbasins using designated points to get smaller subbasins inside.

Are there tools in Arc Hydro Tools or any other tool like QGIS or GRASS that can help me get my goal？

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I have got the subbasin area of every river segment using Arc Hydro Tools：

Martin suggested How to get the subbasin area of each specified river segment？

Now I have some sample stations(the green dots) in the river network, and I'd like to take them as the segment bases, thus I would get more segments, and I want to split the drainage line based on those points and calculate the subbasin area of these new segments：

I think the key is how to make ArcGIS take these green dots as confluences of rivers as well. And all I want is like this schematic photo：

What can I do?