is there any way to make an entity spawn in nether fortresses only?

Hm this solution would cause problems for builds in the Nether but itll work

On Entity spawn

• (Check if its YOUR Entity)

1. (Check if in Nether)
2.  - (Check if block is Nether Brick
3.  - - Spawns Entity or further checks if you want
4.  - Else
5.  - - Cancel (idk if you can so you could also just insta-kill it)
6. Else
7.  - Cancel or Kill

Unrelated but i like the quake pfp