Data validation from external workbook

I have a data workbook which I intend to use as a "master" reference / validation workbook.  Particularly, one column of my "destination" workbook displays a grouping of accounts such as "Medical Expense", which is further subdivided.  My first step is to load each vendor with a default "Expense" group, However, I may wish to allow a change to that group by furnishing a drop-down validation list of other acceptable groups.  Example, Vendor = Costco.  I get my meds there (Medical Expense),  but also buy food (Household Expense), gas (Auto Expense0, etc.  Medical Expense has Prescription Medications and Non-prescription Medications.  Prescription is the default, but I wish to allow the user to change that at data entry time.

 The formula from the validation dialog box reads ("indirect(xlookup(cell referenceI, DIM1_EXP_NAME, DIM1_EXP_CODE)), 0).  The "code_ is the mnemonic for the relevant table.   There is no problem if all the supporting data are in the same workbook as the record-keeping data.  It doesn't work when the ranges and names are in the source file.  I get the error messages that I can't use this type of reference.  Perhaps this can't done,