Selecting view records from a multi-select picklist field

Selecting view records from a multi-select picklist field

I have two views - one a list of topics and one a list of activities.  I want to show a list of all the activities associated with a given topic.  Activities can be associated with many different topics so the TopicRefs field on the Activity form is a multi-select picklist.

I have created a custom action by row on the Topic view that calls a function with TopicRef as a parameter.  The function then uses openURL to open the view.  My openURL statement looks like this:

    thisURL = "#View:Activity_View?TopicRefs=" + ref_id;
    openUrl(thisURL, "same window");

This is where I need help.  The Activity_View always opens with all the activity records.  I've created other openURL calls with views and parameters that work but not filtering on a multi-select picklist field so I suspect that's my problem.

Instead of "TopicRefs=" + ref_id, I would like to have TopicRefs CONTAINS ref_id.  Is this possible?

Thanks.