The building I referred to there (i.e. slated to be the tallest from 2023) is one in the Toranomon-Azabudai area. Toranomon Hills is in Toranomon.
The building, actually buildings, going up on either side of Toranomon Hills Mori Tower (where the Andaz is) will form further parts of Toranomon Hills as a whole. Neither will be taller than Mori Tower though.
Thanks for clarifying, glad to know that the views from the Andaz will remain unobstructed,
for the time being.