A customer asks the question:
"What if I upload a list of cell numbers or email addresses that contain duplicates of what is already in my opt-in lists?"
The TextPower system will ignore duplicates… unless the group assignments are different. If you have groups assigned to an email address (this applies to phone numbers for text messages, too) the system will assign whatever groups are indicated in the new spreadsheet and overwrite the old ones. If, for example, no groups are assigned in the current list and you upload an address and assign "Group A" to it then the list will show that email address with "Group A" assigned to it.
Conversely if you have "Group A" assigned to an address and upload a new list and that same address does not have any groups assigned to it then it will leave the email address in place and remove the "Group A" tag. If you upload an email address that has "Group B" assigned to it and "Group A" is assigned to it in the existing list, that will be overwritten and that email address will now show only "Group B" assigned to it.
This provides a simple and fast way to manage your entire list of cell numbers and email addresses locally, on your own computer, by maintaining the entire list in a simple spreadsheet (as you already know it must be in comma-delimited format). Then you can upload that list anytime you make modifications, or on some schedule that works for you or just as needed. No need to do any actual clicking, entering, managing at all using the AlertManager application - it can all be easily maintained using a common spreadsheet format.