Support filtering by predefined tag field on worksheets

We are trying to get a count of features in an initiative when a custom tag field contains a specific value. The idea is that there could be more than one value in this field but the feature should only be counted at the initiative level if say value PI06 exists as a tag. Similarly, another row of the customer worksheet at initiative level may want the count of features if the same feature field ‘contains’ the value ‘PI07’. Either this should be supported through some new instruction within the arrays or another alternative should be provided in advanced equations to handle this.