Couple of options
If you aren't terribly concerned with efficiency, you can always do something like this:
grep xxx.xxx.xxx.xxx /var/log/logfile | grep google.com
You will only get lines that pass both tests. The first grep acts on the logfile and the second grep acts on the output of the first.
This a quick and dirty way to narrow the results to only the lines you are interested in.
If you are trying to script something or you just want to be a bit more elegant, you will need to do a regular expression.
It would be helpful to see a part of the log file you are searching as reg ex can be challenging to get right sometimes.
Hope this helps!