This works a treat.
A few things to note:
1: My report has 9 subreports and so I loaded up 9 footers numbered 1 to 9. Curiously, the sorting and grouping shows the pseudo groups in the opposite order to the report itself. That is, if the sort and group shows 1 to 9, the report shows 9 to 1. Go figure.
2: I was able to name the pseudo groups in the sorting and grouping and this works fine, making the report design easier to work with as my subreports are sized to the height of the horizontal scroll bar and so you have no idea what they are without selecting them. However, if I named all the pseudo groups, the report ran correctly but gave a pop up criteria input box for every footer. If I leave one footer as a number, this doesn't happen. Until, that is, you save the database, when the groups all cause a criteria input box to appear again. Maybe there is some way of using a text identifier in the pseudo groups without prompting the action???
Edit before posting!! - I modified the report query to include fields with the names of the footers and set them to '1' e.g. enter "PrjActions:1" in an empty column of the query design grid. This gives the footer a field to look at, but has no sorting effect due to all rows having a value of 1. Voilą! My footers now have text names that are meaningful. This doesn't work with spaces in the names (maybe quotation marks would solve this?), so it all has to be one word.
3: The footer keep together property needs to be set on the properties dialog, not the grouping and sorting dialog.
4: If the subreports can be empty, i.e. nothing to show on the report, you can set the footer property to 'Can shrink' or you will get blank space on the report where the empty footer appears.
5: There seems to be a limit of 10 groupings. If you have more subreports than this, then you may have to be even more creative to solve the breaking problem. Post back if this is you and you solve the 'problem'.
Altogether, not a bad workaround.
Thanks again Rickster57.