Price Fixing versus Fee Setting
Price fixing is when prices are set in advance rather than by the free market. It is illegal. The crime of price fixing is subject to federal prosecution by the Antitrust Division of the U.S. Department of Justice under the Sherman Act of 1890.
The general rule is that vendors (providers of products and services) may not agree to set a certain price to create a fixed price within a specific market that has an anti-competitive intent or effect.
Fee setting is a process to determine fees. It is legal. Discussing your fees with other nurses is prudent for determining what is usual and customary in your service area.
I recommend that you openly discuss your fees with your colleagues.