In MS Project, I can figure out how to enter one cost for a cost resource and have it spread out over the entire length of the work package. What I cannot figure out is how to set up the cost resource when its cost varies by period for the work package.

For example, a work package that lasts three weeks and has a total budget for an item of $6,000, 1,000 in week one, 2,000 in week two and 3,000 in week three. I can sort of work around this by breaking the work package into three pieces but I would prefer not to do that. I am hoping there is a better way.