dynamic block

i am wondering if there is a way i could create a dynamic block of a existing block.

ie: section marker for example i have individual blocks/dwgs for a north,south, left and right marker i was wondering if there is a way to create the DB of these but say i wanted to change the south marker but not the others is there a way to do so, so that it automatically updates it in the DB without having to create a new DB

thanks

You can always edit the block in place. Select the block and type "_-bedit".

BEDIT as above and use visibility parameter to arrange the various options.