Custom Properties for Transactions

In Orion NPM, we use Custom Properties to allow people enter the email address(es) of people who should get email alerts on Node and Application issues. We need the same thing for SEUM Transactions. We want Team A to be alerted if Transaction A fails, but Team B to be alerted if Transaction B fails. We are working around this now by creating separate Alerts per Transaction, but obviously that does not scale with more Transactions. If we could have Custom Properties per Transaction, we could put an email address in the transaction and then only have one Alert for all Transactions that sends emails to the people int he Custom Property.