As far as I know the only proviso is you need to be using Dopus Mag.
Beyond that, it's as simple as:
1). Download AROS version of "RunInDOSBOX".
2). Install it to Sys:C
3). Create a root folder for your ms-dos software (Doesn't matter where, and folder structure from within that doesn't matter from then-on-end).
4). Create an assign for the folder you've just created in sys:s/user-startup. Doesn't matter what. For me it will be "assign ms-dos: emulation:computers/pc/ms-dos/software" (without quotes) for example.
And this is where it's a little vague when going off the top of my head. Im not in front of my AROS box. Im on my laptop on a train, had the idea, and dint want to forget before I got home, so thought Id share the idea.
I'll update this for clarity (ie. exact syntax) when I get a chance. The more experienced will probably be able to work it out for now though still.
5). Set up Dopus Mag to use "RunInDOSBOX" every time "ms-dos: ?#.exe" (and ?#.bat (ie. 2 separate entries)) are double clicked.
And that should be it.
Untested in this form, but I do use it for a few specific msdos games/apps. The theory is the same, the method in this post should hopefully just be less work, for all games/apps rather than specific ones.
n.b. please excuse any mistakes in the instructions. As mentioned Im going by memory. Couldn't remember if wildcard is #? or ?# for eg. Same with an assign. Drawing a blank if you put a ":" at the end of the path being assigned to. Pretty sure not, but cant test.
I'll test when I get home, but wont be for a few days, so if anyone wants to give it a try in the meantime, feel free