Then don't. But publishing aggregate salary information is not that. You're making an excuse to avoid sharing information that would help your employees.
You might, for example, try asking them, and seeing how many feel that their privacy would be violated by publishing aggregate anonymous salary data. The answer will be 0.
Keep in mind if you have a reasonable belief that all but one of your employees will collaborate to unmask another's salary, they have ample support to form a union and require internal transparency in the contract. Your threat model is illegitimate.
It depends on how you're aggregating, of course. If I publish an indicative range, I agree that I'm not divulging any private information. (That also happens to be exactly what I'm personally fighting HR/comp in order to be able to do. I want my employees to have this information, but I want that less than I want to protect the privacy of employees who have not chosen to share their information on their own.)
If I publish a names-redacted list of everyone's salary and track/level/job code, or a mean & std-deviation per track/level/job code, I am almost certain to divulge private information of at least one employee. I have spoken with employees on this topic. Publishing their data, even inadvertently (as in the Netflix contest example), does not have anywhere near 100% support.
They can choose disclose it. I will not decide to do so on their behalf.