yes, I do something like that, to achieve group movement, briefly:
all is done within my MapBuilder editor (without manual settings required): 10x10 tiles form a default area (called as cluster), which are automatically subdivided when they contain some homogeneous sub-areas, like an impassable high slope abyss, or water, or badly walkable hill or swamp. Each area move cost is also calculated, and real passability checked too, and stored. It will be used for the high level pathfinding, thus in case of 500x500 tiles, the area array consists of approx. 50x50 clusters = 2500 elements. it can be searched fast enough by A*, taking into account move cost, and later some additional AI influence too.
The tile passability is based on calculated maximum unit size (shown in the picture by different coloured squares) depending on 4 different unit capabilities at the moment, by measuring terrain hight and slope data, plus obstacle data updated periodically, plus moving unit data updated frequently. Each units within a group will do its own, low level pathfinding in small tile arrays, using a faster (but more stupid) solution than A*.
Now I'm ready with these data structures, plus the A* array systems, plus I have the 2 pathfinder algorithm to be used (should be altered a bit of course). What is next is group order and unit behaviour system to be implemented... I realized that making pseudo codes is useful and fun, but requires a lot of chocolate