It exists in MR. I've done something similar a couple of times.
It's not the row link that points to the tree. It's the tree unit that points to the row link. For example, you have the default link in the row format that is column J, you can add another row link which would be column K which you could call Company 2. You'd add the corresponding accounts for company 2 in column K in the row format and save it.
Then you'd open up your tree that has all your entities in it. Under the Row Definitions column, this is where you would specify which Row Link is to be used for that unit of the tree. So wherever company lies in that tree you'd double click in the Row definition column and choose the Company 2 row link.
When you generate your report, the tree is defining which row link to use within the row format.
