triple cascade of drop lists - validation

[clivezgo]

Dropdown Lists / Validation rules
Trying to input information across three decisions

1. Dept 2. Sector 3. Reason

E2	F2	G2
dept	sector	reason
Hoist_Pins	Infeed Conveyor 1

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Using named excel tables I have successfully managed to make a ‘Dept’ downdrop list, using the table below and index/match its headers . The result is used for the sector dropdown list which gives the correct result.

	Trucks	Hoist_Pins
Trucks	General	General
Hoist_Pins		Infeed Conveyor 1
Grader		Infeed Conveyor 2
G_Eye_Scanners		Hoist

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Table of Dept/Sectors

Next, I want to use an individual Sector table, example Hoist_pins table to produce a droplist for infeed conveyor 1 listing the reasons.
These 'sector tables' are dynamic excel tables on individual named sheets.

Hoist_Pins_Table	General	Infeed Conveyor 1	Infeed Conveyor 2
General	Accident	Bearing	Bearing
Infeed Conveyor 1	E-Stop	Cable Fault	Cable Fault
Infeed Conveyor 2	Safety Gate	Chains	Chains
Hoist		Jam Up / Pile Up	Jam Up / Pile Up
Hoist Non-Stops		Motor Faulty	Motor Faulty
Pin Chute		Sensor Faulty	Sensor Faulty
Pin Belt Conveyor		Tripped Out - Elect	Tripped Out - Elect
Pin Shaker Tray		Twisted Pack	Twisted Pack

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This hoist_pins table of sector/faults is named hoist_pins

I cannot make a validation rule based on the 2 previous selections to point to these sector tables and their dropdown lists ….Am I missing something?
I have tried to substitute the table names in the validation box …=INDIRECT(SUBSTITUTE("dummy","dummy",E2)), try and get to the correct sector/faults table.
But is gives the sector list again not finding the correct table or the correct column.
There are different tables for each dept.

thank you for any help..