In the first post Search Federation Options in SharePoint On-Premises I explained and demonstrated the steps required to setup Federated Search Results from 2 different farms.  To show the results I used two seperate web parts.  One confired to show results from Local SharePoint Result Source and other for the Remote resuls.  In this post I will explain the steps required to merge the results and show them as Result Block. 

To achieve this we hav to rely on two things. 

A Query Rule

Allow us to setup rule to make a search query against a different result source or promote the results based on based on some condition and action.  We can create Query Rules at Central Administration, Site Collection and Site Level.   We can also control when to make this rule active. 

A Result Block

A block of search results that will be displayed based ont he query rule.  we can define how much results will be shown, provide “More” links etc.

For more information please read How To Customize SharePoint 2013 Search Results Using Query Rules and Result Sources

Let’s setup the Query Rule and Result block.

The image above is what my results look like before I started.  Two web parts on the search results page.  First I removed the web part from page.  I saw something interesting.  The refinement web part broke. 

When I edit the webpart I found Target not found error.  I may have set the default web part to use the remote result source and 2nd web part to local search results.  Once I set the Refinement Targett to Local Search Results, it did not broke.

Creating the Query Rule

Open Central Adminsitration Manage Service Application Search Service Application Under Queries and Results Click on Query Rules
From  “For what context do you want to configure rule”  select the Local SharePoint Results.  Note: I am selecting it because I want to add this result block in default search results. Then Click New Rule
Type in the Rule name.  You can limit the query based on results Sources, Query Categories and User Seagments.  I am not going into that details.
Select Query Contdition if any based on your requirements.  In my case I remove the condition entirely.
In the Actions section. You can either Add a Promoted Results It looks like Search keywords and best bets in SharePoint 2010 Search.  You just enter the title and URL and Click Save.
Add result Block First you enter the Block Title to make it more clear If you want to configure Query variable and change and test queries you can launc the Query Builder.  From Search this Source Select the Remote result Source created in last blog post. Select the number of Items to show in search results.
Expand the Settings Tab Choose “More” link goes to the following URL and enter the URL of your Search center /pages/results.apsx with ?k={subjectTerms}
In case needed you can control when this query rule will be available and providethe contact.
The result block will be visible now. Clic Save.
The rule will be visible on the Manage Query Rule page.
Now Let’s test the search results.  The first part of search results are Federated.
Click on Show More took me to the remote search center.
I perfomed the exact above step on my other farm to setup two way fedearted results.  Now when I clicked on more to go to other farm the results from first showed up as Federated.

The same procedure is used to get federated results from Office365.  The link to Technet is here https://technet.microsoft.com/en-us/library/dn197173.aspx