How to combine results from 2 servers into 1 combined field?

Hello,

Is there a way to combine the results for 2 different servers (DNS names) into a third field that becomes the 'combined' field? For example, a search returns the following:

Dest      Action    Total
Server1   Failure   10
Server2   Failure   20

How can I combine the results from Server 1 and Server 2 into a new field called Server3 (the combined field) to return the following:

Dest      Action    Total
Server3   Failure   30

The reason I ask is because Server1 and Server2 are really the same server. Server1 is the internal interface and Server2 is the external interface. However, these DNS names are treated as 2 different servers in Splunk and I'd like to combine the Totals that I'm tracking in my dashboards into a new "Server3" field. I hope this makes sense.

Thanks.