Quote Originally Posted by Rogar Demonblud View Post
Yup. We know from Dorukan's epic spell that he had to make an exception for summons so he could get his booty calls.
It's a commonplace of wizard lairs from Azurax Silverhawk to Rary the Traitor and so on that there are special areas where summoning etc work. Look at the 5e version of Mordenkainen's Private Sanctum (PHB p.262) - I don't have my 2E / 3E books to hand - and the caster determines the volume. A skilled caster could cast the spell multiple times to create holes for summoning etc.