Distribution is not permitted under Envato license unless you purchase an extended license from them (which costs upwards of $2000) although it is a good idea to double check/confirm with Envato support on whether extended license really allows distribution.
If an extended license was not purchased, the regular license requires that each customer of this product should purchase a separate license. One site one license is the general requirement of the regular license.
Hope this clarifies for you. Thanks for checking with us.