[R] process evaluation packages (slightly off topic)

[Petr PIKAL]

Dear all

I need to perform some process evaluation. Sorry for not posting data and 
code - I do not have any, I ask only for pointing me to correct direction.

Suppose I have several connected processes P1, P2, ..., Pn. Each process 
takes some time and have some capacity (let say like preparing a dinner 
for several persons - only one stove, limited capacity of utensils, 
heating and cooling takes some time) and some processes can by cyclic (fry 
onion in pan, put it aside, in the same pan fry meat, put an onion and 
some water and simmer for a while...). 

I can prepare some oriented graph (paper/pencil) or Word or drawing 
programme, I can also evaluate whole process by shading spreadsheet cells 
but those two tasks are not connected.

Is there any R package/other software suitable for simplifying or helping 
in such tasks? E.g. When I prepare oriented graph with capacity and time 
for each node is there any automatic way to transfer this graph to 
timeline to see how long whole process will take, where are bottlenecks or 
so?

Thank you

Petr