please consider +ChannelEstimation/PilotSymbolAidedChannelEstimation.m. There, the pilot symbols and their allocations is implemented.
To simulate the effects of pilot symbol contamination, you should use orthogonal pilot symbols within a cell. For this, use the LTE Uplink pilot symbol pattern and orthogonal pilot symbols with a sequence length of at least the number of users in a cell. With this setting I think the pilot symbols in between different cells will not be orthogonal which should lead to exactly what you are looking for. Then you may adjust the inter-link attenuation to obtain different levels of inter-cell interference.
Of course it is also possible to implement your own pilot allocation pattern and orthogonal pilot symbols.
Please also consider whether you want to simulate in TDD or FDD mode.