Lookup Values In Another Table

BACKGROUND

I am desperate to solve this problem but unfortunately I have not been able to figure it out. Below I will outline a design of a database and the desired results.

I know what I want to do but I don’t know how to do it (or whether it is impossible!)

DATABASE DESIGN

The design below is a simplified version of the real thing but it contains the essential information needed to understand my database.

Staff Data
Contains daily data for several members of staff
Staff ID
Staff Name
Date
Data Field 1
Example records:
600-001, Bob Smith, 01/03/2006, 50
600-001, Bob Smith, 02/03/2006, 50
600-001, Bob Smith, 03/03/2006, 50
600-001, Bob Smith, 04/03/2006, 50
600-001, Bob Smith, 05/03/2006, 50
600-002, Jayne Cole, 01/03/2006, 60
600-002, Jayne Cole, 02/03/2006, 60
600-002, Jayne Cole, 03/03/2006, 60
600-002, Jayne Cole, 04/03/2006, 60
600-002, Jayne Cole, 05/03/2006, 60
600-003, Alex Winter, 01/03/2006, 20
600-003, Alex Winter, 02/03/2006, 20
600-003, Alex Winter, 03/03/2006, 20
600-003, Alex Winter, 04/03/2006, 20
600-003, Alex Winter, 05/03/2006, 20

Team Lookup
Shows what team each staff member belongs to and what date this is effective.
Staff ID
Team
Start Date

Example records:
600-001, Sales, 01/01/06
600-002, Sales, 01/01/06
600-003, Accounts, 01/01/06
600-002, Accounts, 04/03/06

Please note:

The first three records show that at the start of the year Bob (600-001) and Jayne (600-002) worked for Sales and that Alex (600-003) worked for Accounts.

The last record shows that from 04/03/06 Jayne switched teams to Accounts

Query Assign Team
Assigns the correct team to Staff ID for each date
Staff ID
Staff Name
Team
Date
Data Field 1
Desired Results:
600-001, Bob Smith, Sales, 01/03/2006, 50
600-001, Bob Smith, Sales, 02/03/2006, 50
600-001, Bob Smith, Sales, 03/03/2006, 50
600-001, Bob Smith, Sales, 04/03/2006, 50
600-001, Bob Smith, Sales, 05/03/2006, 50
600-002, Jayne Cole, Sales, 01/03/2006, 60
600-002, Jayne Cole, Sales, 02/03/2006, 60
600-002, Jayne Cole, Sales, 03/03/2006, 60
600-002, Jayne Cole, Accounts, 04/03/2006, 60
600-002, Jayne Cole, Accounts, 05/03/2006, 60
600-003, Alex Winter, Accounts, 01/03/2006, 20
600-003, Alex Winter, Accounts, 02/03/2006, 20
600-003, Alex Winter, Accounts, 03/03/2006, 20
600-003, Alex Winter, Accounts, 04/03/2006, 20
600-003, Alex Winter, Accounts, 05/03/2006, 20

Query Group By Team
Summarises data by team/date
Team – Group By
Date – Group By
Data Field 1 - Sum
Desired Results:
Sales, 01/03/06, 110
Sales, 02/03/06, 110
Sales, 03/03/06, 110
Sales, 04/03/06, 50
Sales, 05/03/06, 50
Accounts, 01/03/06, 20
Accounts, 02/03/06, 20
Accounts, 03/03/06, 20
Accounts, 04/03/06, 80
Accounts, 05/03/06, 80

PROBLEM: WHAT I AM TRYING TO DO

I don’t know how to get the query “Query Assign Team” to work!!

I would like to lookup up the ‘Staff ID’ and ‘Date’ in “Team Lookup” and return the appropriate value for ‘Team’

If the only two records in Tbl Staff data were:

600-002, Jayne Cole, 03/03/2006, 60
600-002, Jayne Cole, 04/03/2006, 60

I want the query to return:

600-002, Jayne Cole, Sales, 03/03/2006, 60
600-002, Jayne Cole, Accounts, 04/03/2006, 60

Can anybody help me?

Should I be using DLOOKUP? If so, how?
Is VBA the only way around my problem? If so, can you tell me what it is?
Am I attempting the impossible?