Keeping static durations when assigning resources

[Doug Pinkerton]

While I understand the value of having OP calculate durations for me  
when building complex projects, for the current job I simply wish to  
assign resources and durations without them affecting one another. I  
know that Task A will take 2 days if 3 of my resources are assigned  
to it. I do not wish for that to be calculated for me. I do not wish  
to assign efficiency percentages to the resources. I do not wish for  
the addition of a resource to affect the duration of the task. But I  
DO wish for OP to manage the dependencies and to identify resource  
conflicts. Is there a way temporarily to disable the effort/duration  
recalculations? Bear with me if this is a stupid question. I'm new to  
the software.

Thanks,
dp