Model machine Set up time in SimEvent

Hi,

I'm working on SimEvent in order to reproduce the behavior of a manufacturing plant. Due to the complexity I'm actually blocked in the following situation:

I have different 3 different type of entities each with 3 different attributes (entity1 has Attribute 1, entity2 has attribute2 and entity3 has attribute3) that need to be machined by 3 different servers (A B C). Based on the attribute, the entities decide which of the three machines it needs (Attribute1 need MachineA, Attribute2 need B and entity3 need C). The problem is that ONLY 2 out of 3 machines can work at the same time. It means that, if I'm using machine A and B and is entering an entity that need machine C. I need to change the configuration and for example substitute machine B with C in order to process the part. The substitution of the machine requires a certain time (SET UP TIME).

Does someone has an idea of how modelling this case?

my first idea was to schematize the plant in this way , but then I have no Idea of how reproduce the beahviour descripted above. Also OTHER ideas/techniques are accepted.