A mono amp is designed to be used to recieve a signal from one source (without splitting) and deliver to a single source.
However,
You may split the signal past the amp only if the total resistence load is within the amps capability to be stable.
The main reason it is called "MONO" is that it does not produce stereo sound stage. This means that you will get directional sound.
If you use two mono amps and wire them to a stereo output (one to the left and one to the right), then you will still have a stereo output, just using mono amps.