It’s planned but it’s not assigned to any release yet. It’s client side only so it can be done outside a protocol update. So it probably won’t be part of 0.6.0 which will certainly only include protocol changes. Maybe 0.6.1, or 0.5.5 if we want to push that.
In the meantime the best solution is to create a temporary new wallet and import only the addresses you want to park.