Welcome to TRT!!
I've had problems in the past with BJD, but it was only on new specimens that were not entirely healthy. I never had a problem with spreading to other LPS in the tank.
I've found long tentacle plates to be extremely susceptible to the infestation, I attribute it to how delicate they are. Be very careful when transporting the coral home, any where the tissue is lacerated is a potential infection point. Iodine dips can help slow or stop the spread in certain cases. If your colony is branching, just break off the affected heads. Make sure to quarantine any new specimens to make sure they adjust and become less stressed (a week or so) before final placement in the display tank.