Extend How-to Network Routing guide with group routing (#97)

src/pages/how-to/routing-traffic-to-private-networks.mdx

@@ -37,8 +37,13 @@ A routing peer is a node that will route packets between your routed network and
 <Note>
     Only Linux OS nodes can be assigned as routing peers.
 </Note>
+#### Routing group
+A routing group is a set of routing peers each will route packets between your routed network and the other NetBird peers.
+<Note>
+    Only Linux OS nodes can be assigned as routing peers.
+</Note>
 #### High availability routes
-A highly available route is a combination of multiple routes with the same network identifier and ranges. They have different routing peers offering high-available paths for communication between your peers and external networks.
+A highly available route is a combination of multiple routes with the same network identifier and ranges. They have different routing peers or routing peer groups offering highly available paths for communication between your peers and external networks. 
 Nodes connected to routing peers will choose one of them to route packets to external networks based on connection type and defined metrics.
 #### Masquerade
 Masquerade hides other NetBird network IPs behind the routing peer local address when accessing the target Network range. This option allows access to your private networks without configuring routes on your local routers or other devices.
@@ -54,7 +59,7 @@ Distribution groups define that peers that belong to groups set in this field wi
 </Note>
 
 ## Managing network routes
-A network route describes a network you want to connect with your NetBird peers. It has an identifier, a network range, a routing peer, and some parameters available for managing priority and masquerading.
+A network route describes a network you want to connect with your NetBird peers. It has an identifier, a network range, a routing peer or set of peer groups, and some parameters available for managing priority and masquerading.
 
 ### Creating a network route
 Access the `Network Routes` tab and click the `Add Route` button to create a new route.
@@ -82,12 +87,34 @@ Once you fill in the route information, you can click on the `Save` button to sa
 </p>
 Done! Now every peer connected to your routing peer will be able to send traffic to your external network.
 
+### Creating a network route with routing group
+You can use a peer group as routers to automatically add any Linux peers from the groups as routing peers. To do so follow similar steps as above but select the `Peer group` tab. You should have peers assigned to groups.
+If groups have more than one peer you get the [high availability route](#high-availability-routes) out of the box.
+
+<p>
+    <img src="/docs-static/img/how-to-guides/netbird-network-routes-groups-create.png" alt="high-level-dia" className="imagewrapper"/>
+</p>
+
+Once you fill in the route information, you can click on the `Save` button to save your new route.
+
+<p>
+    <img src="/docs-static/img/how-to-guides/netbird-network-routes-groups-saved-new.png" alt="high-level-dia" className="imagewrapper"/>
+</p>
+
+Done! Now every peer connected to the peer member of the groups will be able to send traffic to your external network.
+
 ### Creating highly available routes
 To avoid a single point of failure when managing your network, we recommend installing NetBird on every resource.
 However, you still want to ensure a reliable connection to your private network when running NetBird on every machine is not feasible.
 NetBird Network Routes feature has a High Availability (HA) mode,
 allowing one or more NetBird peers to serve as routing peers for the same private network.
 
+To highly available routes you have two options:
+1. Use a peer group with more than one peer in it. This is covered [above](#creating-a-network-route-with-group-routing).
+2. Add more single peers to the route. 
+
+Let's cover the second option here.
+
 To enable high-available mode, click on `Configure` in the table and select a new peer in the `Routing Peer` field, then select the distribution groups and click on `Add Route`.
 
 In the following example, we are adding the peer `aws-nb-europe-router-az-b` to the `aws-eu-central-1-vpc` route: