Formula field in an alert ?

[n0spam]

Crystal 10 "very" newbie asking for help.

I have the occasional data entry where the ID and date may be duplicates and I need to be able to flag these up for action as if they are indeed actual duplicates, specific action must be taken immediately to rectify.

I have the following formula set up which correctly flags with a D the duplicate entries

if previous({Table1.ID}) = {Table1.ID} and previous ({Table1.Date}) = {Table1.Date} then "D"
else
if next({Table1.ID}) = {Table1.ID} and next({Table1.Date}) = {Table1.Date}then "D"
else
""

Is it possible to use a formula field as a parameter in an alert ?