ANN with communication between nodes of same layer
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]
output: [neuron6]


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?