Is it possible to Edit Row Data for a repeater differently depending on whether Item.column is empty?

I’m wondering how to conditionally Edit Row Data for a repeater.

I have a repeater that has a row for each of 30 vehicles. One of the columns in the repeater is a list of commands to which the vehicle has been assigned. Commands are separated by ', '. Vehicles are assigned while creating a new command.
As each vehicle is assigned, I mark the row in the repeater.

When saving the new command, I call Edit Row Data on the marked rows and want to either set the Column to the name of the newly created command or append the name of the newly created command (prefixed by ', ') to the previous contents of the Commands column, depending on whether the Commands column was empty for that Item. I don’t want to prefix the first item in the list with ', '. Is this possible?

I’ve figured it out…it can be done using three separate Edit Row Data statements.
I have to start with a blank space in the Commands column for each Item.
The first Edit Row Data appends ', ’ to all marked rows.
The second Edit Row Data replaces ’ , ’ with ’ ’ for all rows in which Item.Commands == ’ , '.
The third Edit Row Data appends the new Command’s name to all marked rows.