How do I change the default metric subdivision? E.g. notating a Turkish piece in 9/8, the 8ths grouped 2223, a very common Turkish meter. Dorico insists on grouping the 8ths as 333, so that my entry of quarter, quarter, quarter, dotted quarter comes out as quarter, eighth tied to eighth, quarter, dotted quarter. Changing the Rhythmic Grid resolution from 8ths to quarters has no effect.
In the time signature panel (on the right), under create time signature, select aggregate and then define the time signature to be 2/8 2/8 2/8 3/8. Set your rhythmic grid to 8th notes in the Write>Rhythmic grid menu item. This will create the subdivisions you want and will show dotted bar lines between the sections in the score.
Use , then you’ll get the right time signature. [2+2+2+3]/8
To have the time signature appear as 8/8 but beam as 2+2+2+3, enter Shift-M “[2+2+2+3]/8”
I think you need to use brackets in the popover: [2+2+2+3]/8
Some people here already rock on those very refined subjects ! I suggest jsummerskvi could add [Solved] at the beginning of its thread, to make it clear for everyone the answer is there 
Thank you to all!