Move data from one file group t0 another

as per my previous post "Filestream Files" (still awaiting if anyone can answer) i have issues with disk space available where one of the filestream file group resides.
i can create another filegroup with a file and move some old data from existing file group to new file group. and than i will mark it read only so no data gets written to it.
can someone please guide me how i can move data from one file group to another?

Please Take a llok at here:
It might be helpful for you.

this doesn't work for filestream :frowning: