Validation Rule.

I have an Access database and want to restrict a field to only accept certain data. For example, i have another table with the employee numbers 1, 2, 3, 4, 5, i want the user to be able to insert 1, 2, 3, 4, 5 but when they try to insert 10 etc they will recieve an error message. If it makes it easier i have another table thaholds all employee numbers so if it possible to link the validation to the table that would be great.

Thanks.

Wouldn't creating a look up field between the two provide the same thing and turn the limit to list to Y?