Feeding multiple 50 ohm terminated outputs from a single 50 ohm source without signal degradation
So, energy conservation says that if you have N loads that you want to put the same energy into (which is synonymous with the same voltage, given constant termination), you need N times the energy. 

You'll have to buy or build a distribution amplifier.

Note that termination is not necessarily the same as wave impedance – you can, using one of many architectures, build a splitter that conserves the transmission line impedance (i.e. 1× 50Ω in, N× 50Ω out), but that will, too, divide the power.