Yes! That is definitely possible. You should know that not all network topologies are layered. You could also have a network which consists of loose neurons which are connected to one another in a more liquid way:
The reason we have 'layers' in networks is not because they add functionality, but because they make coding easier and more overseeable. When you have for example this network:
input: [neuron1, neuron2]
hiddenlayer: [neuron3, neuron4, neuron5]
that is exactly the same as:
[neuron1, neuron2, neuron3, neuron4, neuron5, neuron6]
Because all neurons get activated sequentially.
So what kind of synapses do you want to create inside a layer? Recurrent or feedforward?