Holding parameter values when report is refreshed due to custom buttons used for expand/collapse groups

Question

This may be as simple as it can't be done, but I have to ask. :) I am building a report using Report Builder 3.0. The report contains a table which also has Grouping established. I wanted to give the user an easy way to expand/collapse all rows of the table, so I used the method of creating a parameter with two values (0 for collapse, 1 for expand), tied the visibility of the group to the parameter using an expression in the Hidden Property for the group. Then I created two text boxes for Expand and Collapse and added the respective parameter/value in the Action in the text box properties.

At this point, everything works as intended. Here is where I run into the issue. I added another parameter, lets just call it "Location". The parameter is a text data type that allows multiple values and gets it available values from dataset/query in the same report. This is where I am guessing what I want may not be possible. When I select my Location(s), then run the report it all looks good. However, when I click on one of the Expand/Collapse text boxes, it clears out the values that I selected for the location(s). I am guessing this is due to the fact that the available values for the Location parameter is set via a query at run time. Is there any way to maintain the values for the Location parameter when triggering the expand/collapse buttons?

Thanks in advance!