The organisation, which is called the Little Guys Radio Association, comprises talkSPORT, Premier Christian Radio, Sunrise Radio, Club Asia and Spectrum Radio. It has been formed to campaign for electronic measurement to be introduced in favour of the diary system operated by Rajar.
MacKenzie, the chairman and chief executive of The Wireless Group, has supported the move to an electronic watch-based system because he believes that smaller radio stations are being penalised under the Rajar system.
MacKenzie argued that the diary system favours large stations with big marketing budgets. Sunrise Radio also criticised the Rajar system of measurement.
It alleged that it under-represents Asian listeners.
The LGRA is opening associate membership to advertisers, media agencies and research groups that will back its campaign for a change in the measurement system.
MacKenzie said: "The CRCA is a club for the big boys. It's a fat cat organisation for fat cats by fat cats. It does nothing for the little guy - and that's why we're coming together."
The formation of the LGRA is MacKenzie's latest move in a campaign against the radio establishment. TalkSPORT has already begun a trial of the new electronic system and claims that its results more accurately reflect the listening audience.
Ironically, talkSPORT has been performing well under Rajar's measurement system, with a 10 per cent year-on-year growth in reach to 2.47 million.
However, MacKenzie argues that its audience is larger.