I am trying to build a table and formula to look up the phase of a project
based on the week that a piece of work was done. I need to do this for
multiple projects with different start dates. I have built the table listed
below. I can change the Phase start date to End date if needed.

Column A Column B Column C
Project Phase Start Date Phase Name
Project A 5/21/2007 Concept
Project A 9/30/2007 Plan
Project A 10/30/2007 Develop
Project B 2/28/2007 Concept
Project B 5/31/2007 Plan
Project A 12/1/2007 Rollout


I have been trying to do this using the concatenate feature to combine the
Project and Date columns, then use VLOOKUP to find the appropriate Phase, but
I get mostly NAs or inconsistent data at best. An example of what I need to
see is below:

Assuming that project A had work performed for the week of 5/25/07, I would
expect a result of Concept, because the next date for Project A in the table
is 9/30/07. Therefore, any date for Project A between 5/25/07 and 9/29/07
should have a result of Concept. In addition, for a week end date of
11/23/07 I would expect a result of Develop, and any dates after 12/1/07
should have a result of Rollout. Is there any way to build this table and
formula to return these results?

Any help anyone can provide would be greatly appreciated.

Thanks,
Rob