Am I allowed to use the separator :: in the contains field of a condition for an email trigger?

You can definitely trigger email based on some conditions. Do you mean that values coming in embedded variable coming from contact list contains ::

I want to use an operator in the field to state that the embedded data can contain AB or BC or CD or DE (AB::BC::CD::DE)

You can add conditions within OR operator can't be used while you can use nested if . If or if or...

Sorry let me reiterate. I have several conditions for the email notification trigger. The last condition is an AND with an embedded data condition that contains any of the following text AB::BC::CD::DE. Can I use the :: for this condition. Will the system look for any of those text values between the :: or am I to create an individual condition for each text value to look up?

You have to create individual condition

Ok. Thank you for confirming my suspicions.