Number of possible permutations for N groups from I items where each item is of a different size but group total is fixed across groups

Question

this is my first post.

I am not sure how to approach this problem, I would like direction or even an algebraic solution please.

I have to sort 70 different sized items out into 12 groups. Each group has the same total allowed size, the size has minimum and maximum.

I want to know how to work out the total possible permutations there are? How would I go about working this out?

Thanks