Minor optimisations when editing and viewing domains

app/Models/System.php

@@ -115,9 +115,10 @@ class System extends Model
 	public function sessions()
 	{
 		return $this->belongsToMany(Zone::class)
-			->select(['id','zones.zone_id','domain_id','active'])
+			->select(['zones.id','zones.zone_id','domain_id','zones.active'])
+			->join('domains',['domains.id'=>'zones.domain_id'])
 			->withPivot(['sespass','pktpass','ticpass','fixpass','zt_ipv4','zt_ipv6','default'])
-			->dontCache();
+			->orderBy('domains.name');
 	}
 
 	/**
@@ -301,6 +302,13 @@ class System extends Model
 		}
 	}
 
+	public function inDomain(Domain $o): bool
+	{
+		return $this->addresses
+			->filter(fn($item)=>$item->zone->domain_id === $o->id)
+			->count() > 0;
+	}
+
 	/**
 	 * Return the system's address in the same zone
 	 * This function can filter based on the address type needed.