Interim Solution for Custom Object Contact-Level Filtering

Hi Team,

We have a custom object related to closed leads that we use for a nurturing campaign. Currently:

• The custom object is linked at the Account level.

• As a result, all contacts associated with the account receives the email.

• Our goal is to have only the specific contact associated with the closed lead receive the email.

• We plan to eventually update the custom object relationship to the Contact level.

Interim solution:
Since the custom object already contains a Contact ID, is there a way to:

• Match/filter the Custom Object Contact ID against the Marketo Lead/Contact ID, or

• Use another Smart List-only workaround to exclude contacts who are not associated with that specific closed lead ?

Any guidance on an interim solution would be greatly appreciated.

Regards,
Akshat