You certainly can get pin converters, though if you have an unused drive bay I'd recommend a fan controller.
The NZXT Sentry Mix 2 fan controller has always worked well for me, and I've had it in 2 of my custom rigs. It supports 6 fans, has changable LED color display, and has very long cables for easy cable/ fan management. Good for both mid-tower and full-tower builds.
**One caveat, it gets powered by moelx not SATA, so make sure your PSU has a molex adapter available before buying this specific fan controller.
I've never tried either of those, though technically they look like they would do what you need.
After glancing at their reviews they both look like they are hit or miss with their software, so personally if it was between those and just getting the pin converters I'd go with the pin converters.