I have the following validation rule that works perfectly which makes mandatory `[Customer]` and `[Member]` columns if column `[Feedback Type]` equals "Ticket" from a drop down list:

    =IF([Feedback Type]="Ticket",AND([Customer]<>"",AND([Member]<>"")),TRUE)

I need further validation rule but have no idea if it is possible to build further validations; what I also need is:

If `[Feedback Type]` equals **"Ticket" or "Customer"** from a drop down list then `[Customer]` and `[Member]` must be mandatory.

Ideally I would like also the following validation rule included:

If the column `[Feedback Type]` equals "Colleague" from a drop down list then `[Colleague]` must be mandatory but not `[Customer]` and `[Member]`

Hope the above makes sense!

Thanks