Two stacks of 4300 switches

I'm not sure if the cascade rule is still a think.   We have two locations - each with a stack of 6 Netgear switches (4300)

We are moving two a new building and adding yet another large group of people so effectively we'll need a 3rd stack.

The owners do not want to spend money on new equipment, they want to reuse the current equipment  (i can't blame them).

I've never had two stacks in the same building.   Is there any issue with having two or three stacks of 6 switches.   

I know the maximum number of switches in a stack is 8 but we are connecting multiple stacks.