Widgets for multiple selection (like excel filter on a column)

Hi,  I am looking for some guidance on appropriate widets/strategy on how to accomplish this. I am using GoogleChartTimeline to render my data (this used microflow to supply the data). I need to filter the data that is rendered by set of values for a particular attribute. I need to allow the user to select one or many values for this attribute in the UI. Then the above values need to be passed to the microflow. THe microflow needs to filter the data based on the user selected values for rendering. My question is what is the best way/widget to allow mutiple selection for an attribute values like radio or check(remember these are not hardcoded) . THe values need to be retrieved from DB and show in the UI so that the user can select any of those values (like Excel filter on a column with multiple selection).  Also, now I am querying the data in mcroflow(that supplies data to GoogleChart timeline) using Xpath. I was wondering is there any way dynamically build this Xpath query . May be I could declare a parameter and set the value and then use it. I am not sure. I appreciate any input on what widgets/UI will be appropriate to acomplish this.  
1 answers

Create a helper object where you store all the values the user want to see in the chart. You can then use a microflow that based on this helper object retrieves all the values and creates the chart.  Hope this helps.