Two Dependant Dropdowns from two tables in one Form

[SG1]

I'm building an App to record appointments at hospitals for a charity helping children needing surgery.

In the appointments form (see below), I need the hospital staff and hospital service validation to depend on the hospital chosen. When a hospital is chosen, only staff and services related to that hospital should show up on the validaton list. 

In the Appointments table the ValidIF of the Hospital Key is Hospital Staff[Hospital] and the ValidIF of the Hpspital Staff Key is Hospital Staff[Hospital Staff Key] and that works perfectly. The problem is how to do a similar validation in the Hospital Service Key using the Hospital Key chosen.

These are the 5 tables.

Many thanks in advance for your help.

[Marc_Dillon · Accepted solution]

https://help.appsheet.com/en/articles/2357314-select

[SG1]

Used this in ValidIF. It worked Marc. Thanks a million

SELECT(Hospital Services[Hospital Service Key], ([Hospital] = [_THISROW].[Hospital Key]))