Fan splitter is most likely what you need. It allows you to connect two fans to one header. "Stacking" two of these into one (three splitters in total) can produce four fan outputs from one mobo header, and most common fans pull a small enough current that this can work just fine. There even are some 3-output splitters, like this:
http://www.newegg.com/Product/Product.aspx?Item=N82E16812423163&cm_re=fan_splitter-_-12-423-163-_-Product
It is true that, when using fan splitters, only the speed of ONE of the fans will be displayed by the mobo system. Any mobo header can only deal with ONE fan's speed signal, so splitters are designed to ignore all but one fan. So what? You really do NOT need to know the speed of your all fans. BUT this also means that your mobo cannot monitor ALL your fans for failure, so you need to check them every few months to be sure they all are still turning.
NOTE1: there are 3-pin and 4-pin fan systems. It's getting hard to find 3-pin fan splitters. But you CAN use a 4-pin splitter with either 3- or 4-pin fans, no problem.
NOTE2: Mobo headers that use true PWM Mode to control their fans can NOT control 3-pin fan speeds. Only 4-pin headers can use PWM Mode. BUT too many mobos today use 4-pin headers but only use the older 3-pin voltage Control Mode on those headers. That's OK sort of - BOTH 3- and 4-pin fans CAN be controlled by Voltage Control Mode.
NOTE3: There are two similar devices on the market. A SPLITTER has one female fan connector to plug into a mobo header and two or more male fan output connectors. It connects all its fans to the power from the mobo header. A HUB, on the other hand, has an additional connector - one that must plug into a power output (either 4-pin Molex or SATA) directly from the PSU. This device can ONLY work when connected to a mobo 4-pin header that really does use PWM Mode. Most of these devices have several fan output male arms. They MUST be used with 4-pin fans. They connect all their fans to the PSU power source (NOT the mobo power) and then share the PWM signal from the mobo header to control the fans. (There are two makers of HUBS with a different design that CAN control 3-pin fans, too.) The advantage of a HUB is that you can control many 4-pin fans from the PWM signal from ONE mobo header. But for a few fans in total, a SPLITTER is much simpler.
NOTE4: Whether you use a Splitter or a Hub, all the fans connected to it will get the same speed signals. So IF they all are the same fans, they will run at the same speeds. BUT if they are different models, their speeds may differ. Either way, you will only be able to have the computer display ONE fan's speed per mobo header.