In the measure screenshot that Gerald shared, you can use the drop-down menu next to "Match" to select "not equals" or "not contains". This should help you to exclude the IP addresses that you do not want to track. Please note that changes to Business Transactions and measures are not retroactive. They are from the point where the change was made onward, this means that you could still see old data being displayed even after you make a change, depending on the timeframe you are displaying.
I'd actually stick with using the matches, equals, or contains and avoiding the negative ones (not contains, not equals, etc...). Using a lower threshold of 0 as in Gerald's post means it is only including PurePaths that don't have that IP in them.
I think it might be because when you are saying not matches, if at any point there is an IP that doesn't match the one you're trying to filter out then the count will be one regardless of whether the one you want to exclude shows up later meaning that it will be including even if that IP shows up. The alternative of matching it but setting a lower threshold of 0 says that it will only be included if there are 0 occurrences of that IP overall in the PurePath.
What I don't like about negative compare is the complexity you get when you need to filter for more complex terms and have to use negative lookbehind regex.
To overcome the described problems with my solution, there is still the possibility to tune the measure with the setting occurrences on purepath. Also changing the aggregation to max or min helps in some usecases.
You can us regex to tackle this, however regex have bit higher server overhead. Here is a regex from Useful Regular Expressions Page:
1. Capture Any Client IPv4 Except List of IP Address:
Any IP except: 188.8.131.52 or 184.108.40.206 or 220.127.116.11
Here, enlist IP addresses and escape dots by \