DeepSkyStacker master light frames?

[sploo]

When I run a stack using DeepSkyStacker (with light, dark, bias and flat frames) it generates a "master" image for each of the dark, bias and flat groups. I understand you can then delete the original dark, bias and flat captures and use those master frames for further stacking operations.

Generally I will run a stacking operation on a night's shooting to take a look at the output from just that night; so I'll end up with 'O' (the output image), 'MD', 'MB' and 'MF' (the master dark, bias and flat frames), and of course my original light frames 'LLLLL'.

If I later combine multiple night's shoots of the same target (each with their own set of light, dark, bias and flat frames) I can set up each group in DSS with its light frames and just the three master dark, bias and flat images. I.e.:

Main group: 'LLLLLL', 'MD', 'MB' and 'MF' from shoot 1
Group 1: 'LLLLLL', 'MD', 'MB' and 'MF' from shoot 2
Group 2: 'LLLLLL', 'MD', 'MB' and 'MF' from shoot 3
...

Instead, is there a way to create "master light" frames; such that you use the output image 'O' from each individual shoot? I assume that as each output file has had the bias, dark, and flat data applied, you wouldn't need to add them again; thus you'd only be stacking a single file from each shoot. E.g.:

Main group: 'O' from shoot 1
Group 1: 'O' from shoot 2
Group 2: 'O' from shoot 3

The problem is that the output file from each shoot is usually a different resolution (due to the mosaic/intersection combination of light frames); so DSS refuses to stack them. Even if this worked, is there any point? Would this stacking method produce the same results as re-running all the light frames from each shoot in a single stacking operation?