As federally mandated health insurance exchanges begin in October under the Affordable Care Act, some retirees are already finding out what is soon to come.

Some companies are moving away from retiree health plans as they become too cost prohibitive and are having their retired employees sign up for private health insurance exchanges, The Wall Street Journal reports.

AARP's Ariel Gonzalez tells the Journal that the senior citizen advocacy group generally sees the exchanges as a positive, but doesn't want to see companies use them to cut benefits.

Extend Health is one group offering private exchanges to pick Medicare plans. Companies provide their retirees with a cash amount that can be used to pick a plan that best meets their needs.

Bryce Williams of Towers Watson Exchange Solutions, the parent company of Extend Health, told the Journal that most people find the exchanges scary at first. Only about 10 percent of corporate retirees have used them, he said, but he sees that percentage rising as more companies find they can't afford to fund retiree health care.

"There are still quite a few others coming," he said. "We are at the front end of the wave."