There isn't any way to do "assignments" like you want with "v".
Your long chain of address[]=... can be written shorter, however. Instead of
address[0]=address[3], address[1]=addess[4], address[2]=address[5]
you can write
address[0..2]=address[3..5]
What RAM part are you working on what RAM part are you using to make it?
In general, if the sub-part is 1/8 the size of the part you are making, you should be able to use assignments like this
CHIP RAM64 {
IN in[16], load, address[6];
OUT out[16];
PARTS:
...
RAM8(address=address[3..5], ...);
--Mark