Image Viewer shortcut reopening Target Program

I use the Do image viewer to browse my photos and decide if I need to use a photo editor. I have used a short cut on my Do image viewer to open pictures in Photoshop and if I go back to the image viewer with Photoshop still open and use the same shortcut again on another picture, it displays in the already open Photoshop with no problem. I made a shortcut for a different image editor called Luminar and while it works great for the first image, if I try to use the shortcut with another picture, a second incidence of Luminar opens along side the first. Is there a way to force the shortcut to allow only one of the targeted program to be open at a time?

I'm extremely grateful to all the developers of Do for creating what I consider an essential program.

It's up to Luminar what it does when launched, and whether it sends the file to an existing instance or opens a new one.

They may have a command line argument to change what they do, but it's usually automatic and I can't find any information, except some (old) messages in their support forum saying they don't have a command line interface at all.

I would ask them if there is a way to do it. Opus just runs the program with the arguments you tell it to use (e.g. the filepath), the same as if you ran it from a Command Prompt, and the rest is up to the program.

Thanks once again Leo.