Dynamic blocks - too many visibilities

[nextvkin]

I inherited a drawing with a large number of dynamic blocks that have too many visibilities causing the file to be very large, so in this particular drawing I want to reduce the blocks just to their current visibility - is this possible without opening every block to do it?
Hopeful, thanks.

[Ed Jobe]

The only thing I can think of besides writing custom code, is to redefine the block.