How can I create a more realistic multiple gate entrance model ?

Hi ,

I have created a model in simulink where there is an entity generator followed by an output switch which drives the entities to queues just before 8 gates/servers. My model is based on this model:

http://www.mathworks.com/help/simevents/examples/comparing-queue-server-combinations.html

but instead of having 3 queues leading to 3 gates/servers , my model has 8.

I would also like the model to be able to enable/add or disable/remove a server/gate based on the length (or the waiting time) of (the)previous gate(s).So in the begining there should be 2 open gates and as the generator produces more entities and the length of the queues of those two gates get bigger,I need the 3rd gate to get opened and then the 4th and so on.In the opposite situation when the queues get smaller I would like the gates/servers to get closed(disable). In general I would like to model the procedure in which when there is a higher incoming rate of entities(cars/trucks), more gates get opened and also when there is a lower icoming rate of entities those gates get closed(disabled)-in order to achive a better(more realistic) service model -.

Ι have not found any example model in matlab/simulink documentation which satisfies the above criteria and I would greatly appreciate any ideas or comments on how it can be built.

Thanks in advance.