Hello @TomasL44 you can make any unit in the indoor map bookable. If the ASSIGNMENT_TYPE of the particular room that you plan to repurpose as a lactation station is set to Null or Not Assignable, you can enable assignment for it in Space Planner (see screenshot).
Following that, you can create a Hotel named Lactation Stations and then assign that room to that area and optionally, assign people to it too and restrict bookings so only a limited number of people can book it. This way you can ensure it is used only for its intended purpose by those who need that space.
In this example, I am repurposing a storage room (has full privacy) by enabling assignment. You can even edit other attributes from the Properties view, if needed.