Krishna,
I was able to get it to finally work, after your suggestions and some more documentation.
I modified the ECC function to allow for 2 variables as input, Storenumber and EmployeeNumber.
I made the EmployeeNumber return a single record, thereby making it the KEY to my function. I added logic to return the Storenumber employees also. I also ensured the input variables had the same name as the table variables that were returned.
I then redid the project. I used the Storenumber, EmployeeNumber, LastName and FirstName as the fields on my Entity Type, and made EmployeeNumber the Key and StoreNumber to be a filter.
I then mapped the Read to have the EmployeeNumber as Input and Output.
I then mapped the Query to have both EmployeeNumber and StoreNumber as Input, to the appropriate import variables.
Therefore when I call it with ('123456'), it triggers the Read service and uses that number as the key and returns a single value.
When I call with ?$filter=StoreNumber eq '1234', it returns the proper records by using the query.
So it is working great now, but it took some more digging.
Thanks for the help,
Mike