3 solutions
If you are removing the models from a script
1. Have the scripts call a central resource to remove the models. If they are removing the lamp post ID, store the position and radius in a table.
2. Manually store the position and radius in a table.
If you are removing the models with map editor (.map files)
3. getElementsByType("removeWorldObject") will return custom elements that represent each removal. Use getElementData on each element and get posX, posY, posZ and radius data fields, on the ones with the right model.
Once you have the x, y, z and radius of the world removals, you can skip IPL entries of your lamp post that contain a position within this sphere (defined by x, y,z and radius).
To determine if a point is within a sphere, it's a simple distance check
x1, y1, z1
x2, y2, z2
radius
distance = math.sqrt((x2-x1)^2 + (y2-y1)^2 + (z2-z1)^2)
if distance < radius then
-- Point is within sphere
else
-- Point is outside
end