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Try using a different trigger based on one table, and then do a “Find Records” action to look for records that match in the other table. For example, the trigger could be when a [mentee] has a city and a field of activity, but no linked [pair]. Then have a “Find Records” action that looks for a [mentor] in the same city with the same field of activity. Note however, if mentees could have multiple cities or fields of activities, it might be difficult to find a partial match (e.g. a mentor in one of the cities with only one of the fields of activities) without scripting.