diff --git a/lib/net/pool.js b/lib/net/pool.js
index 90bb6270..2c4d2f32 100644
--- a/lib/net/pool.js
+++ b/lib/net/pool.js
@@ -10,7 +10,6 @@ const assert = require('bsert');
 const EventEmitter = require('events');
 const {Lock} = require('bmutex');
 const IP = require('binet');
-const dns = require('bdns');
 const tcp = require('btcp');
 const UPNP = require('bupnp');
 const socks = require('bsocks');
@@ -85,6 +84,7 @@ class Pool extends EventEmitter {
     this.pendingFilter = null;
     this.refillTimer = null;
     this.discoverTimer = null;
+    this.connectedGroups = new Set();
 
     this.checkpoints = false;
     this.headerChain = new List();
@@ -663,6 +663,7 @@ class Pool extends EventEmitter {
     this.logger.info('Adding loader peer (%s).', peer.hostname());
 
     this.peers.add(peer);
+    this.connectedGroups.add(addr.getGroup());
 
     this.setLoader(peer);
   }
@@ -3367,6 +3368,7 @@ class Pool extends EventEmitter {
 
       if (!entry)
         break;
+
       const addr = entry.addr;
 
       if (this.peers.has(addr.hostname))
@@ -3390,6 +3392,10 @@ class Pool extends EventEmitter {
       if (this.options.brontideOnly && !addr.hasKey())
         continue;
 
+      // Don't connect to outbound peers in the same group.
+      if (this.connectedGroups.has(addr.getGroup()))
+        continue;
+
       if (i < pc30 && now - entry.lastAttempt < 600)
         continue;
 
@@ -3428,6 +3434,7 @@ class Pool extends EventEmitter {
     const peer = this.createOutbound(addr);
 
     this.peers.add(peer);
+    this.connectedGroups.add(addr.getGroup());
 
     this.emit('peer', peer);
   }
@@ -3482,6 +3489,9 @@ class Pool extends EventEmitter {
   removePeer(peer) {
     this.peers.remove(peer);
 
+    if (peer.outbound)
+      this.connectedGroups.delete(peer.address.getGroup());
+
     for (const hash of peer.blockMap.keys())
       this.resolveBlock(peer, hash);
 
diff --git a/test/net-netaddress-test.js b/test/net-netaddress-test.js
index 222d2087..fa4a275b 100644
--- a/test/net-netaddress-test.js
+++ b/test/net-netaddress-test.js
@@ -1,5 +1,14 @@
 'use strict';
 
+/* Parts of this software are based on bitcoin/bitcoin:
+ *   Copyright (c) 2009-2019, The Bitcoin Core Developers (MIT License).
+ *   Copyright (c) 2009-2019, The Bitcoin Developers (MIT License).
+ *   https://github.com/bitcoin/bitcoin
+ *
+ * Resources:
+ *   https://github.com/bitcoin/bitcoin/blob/46fc4d1a24c88e797d6080336e3828e45e39c3fd/src/test/netbase_tests.cpp
+ */
+
 const assert = require('bsert');
 const NetAddress = require('../lib/net/netaddress');
 const Network = require('../lib/protocol/network');