diff --git a/src/ServerContext.ts b/src/ServerContext.ts
index bccfcf2..b55a8b1 100644
--- a/src/ServerContext.ts
+++ b/src/ServerContext.ts
@@ -2,4 +2,5 @@ import { InterchangeSystem } from "./entities/InterchangeSystem";
 
 export interface ServerContext {
   systems: InterchangeSystem[];
+  findSystemById: (id: string) => InterchangeSystem | null;
 }
diff --git a/src/resolvers/StopResolvers.ts b/src/resolvers/StopResolvers.ts
index 9a2b55a..89f6444 100644
--- a/src/resolvers/StopResolvers.ts
+++ b/src/resolvers/StopResolvers.ts
@@ -4,14 +4,14 @@ import { ServerContext } from "../ServerContext";
 export const StopResolvers: Resolvers<ServerContext> = {
   Stop: {
     orderedStops: async (parent, args, contextValue, _info) => {
-      const system = contextValue.systems.find((system) => system.id === parent.id);
+      const system = contextValue.findSystemById(parent.id);
       if (!system) {
         return [];
       }
       return await system.shuttleRepository.getOrderedStopsByStopId(parent.id);
     },
     etas: async (parent, args, contextValue, _info) => {
-      const system = contextValue.systems.find((system) => system.id === parent.id);
+      const system = contextValue.findSystemById(parent.id);
       if (!system) {
         return [];
       }
diff --git a/src/resolvers/SystemResolvers.ts b/src/resolvers/SystemResolvers.ts
index dd3c856..8ea01ae 100644
--- a/src/resolvers/SystemResolvers.ts
+++ b/src/resolvers/SystemResolvers.ts
@@ -3,16 +3,16 @@ import { ServerContext } from "../ServerContext";
 
 export const SystemResolvers: Resolvers<ServerContext> = {
   System: {
-    routes: async (parent, args, contextValue, _info) => {
-      const system = contextValue.systems.find((system) => system.id === parent.id);
+    routes: async (parent, _args, contextValue, _info) => {
+      const system = contextValue.findSystemById(parent.id);
       if (!system) {
         return [];
       }
 
       return await system.shuttleRepository.getRoutesBySystemId(parent.id);
     },
-    stops: async (parent, args, contextValue, _info) => {
-      const system = contextValue.systems.find((system) => system.id === parent.id);
+    stops: async (parent, _args, contextValue, _info) => {
+      const system = contextValue.findSystemById(parent.id);
       if (!system) {
         return [];
       }
@@ -21,7 +21,7 @@ export const SystemResolvers: Resolvers<ServerContext> = {
     },
     stop: async (parent, args, contextValue, _info) => {
       if (!args.id) return null;
-      const system = contextValue.systems.find((system) => system.id === parent.id);
+      const system = contextValue.findSystemById(parent.id);
       if (!system) {
         return null;
       }
@@ -40,7 +40,7 @@ export const SystemResolvers: Resolvers<ServerContext> = {
     },
     route: async (parent, args, contextValue, _info) => {
       if (!args.id) return null;
-      const system = contextValue.systems.find((system) => system.id === parent.id);
+      const system = contextValue.findSystemById(parent.id);
       if (!system) {
         return null;
       }
@@ -59,7 +59,7 @@ export const SystemResolvers: Resolvers<ServerContext> = {
     },
     shuttle: async (parent, args, contextValue, _info) => {
       if (!args.id) return null;
-      const system = contextValue.systems.find((system) => system.id === parent.id);
+      const system = contextValue.findSystemById(parent.id);
       if (!system) {
         return null;
       }
@@ -71,7 +71,7 @@ export const SystemResolvers: Resolvers<ServerContext> = {
       return shuttle;
     },
     shuttles: async (parent, args, contextValue, _info) => {
-      const system = contextValue.systems.find((system) => system.id === parent.id);
+      const system = contextValue.findSystemById(parent.id);
       if (!system) {
         return [];
       }