i have been searching the forums for 2 days to find an answer to my issue but w/o any luck.

can anyone tell me if this is possible and if so point me in the right direction?

i have a top category with products A, B, C, D, E, each product has one attribute that must be selected via radio bttn.

i want to sell these products in case and multiple case lots only. each case must total 12 products in all. no more or less.

so a customer would have to make up a case of 12 products using any combination of products A thru E and choosing the req'd attribute for each.

is it possible to require this case total?
can this work in multiples of a set number?
in my case multiples of 12? i.e. a total of 12,24,36, etc... would be recognized as 1,2 and 3 cases respectively. totals not equaling a multiple of 12 would cause an error mssg or something.

i have looked into the "products attribute grid" this accomplishes some of my goals but not the qty restrictions.

any thoughts?

thx in advance