It is definitely possible. The easiest case is you have a single neighbor IP address and replace it with the same string each time. There is a good example of this in the example scripts in the app directory. The script name is 'Script_replaceText.txt'. The default language for KSS is VBscript so you can create scripts to manage most things.
More complex is having multiple KNOWN neighbors and strings to replace them with. You can manage this a couple of ways:
An 'if' statement for each possibility:
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if instr(Fields.VarCleanMessageText), <IP Address 1> then
replace(Fields.VarCleanMessageText, <IP Address 1>, <Hostname1>)
end if
if instr(Fields.VarCleanMessageText), <IP Address 2> then
replace(Fields.VarCleanMessageText, <IP Address 2>, <Hostname 2>)
end if
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You can also use 'case' statements to do the same thing.