Combine url with multiple same args from submitted form

I have a form with multiple checkboxes, all called filter. When the form gets submitted, they get added to the URL, "http://ift.tt/2gT8lWr", as expected.

When there are multiple checkboxes selected, they get added to the url like so: "http://ift.tt/2h2rClL".

Is it possible to change this somehow? I need them in the url as "http://ift.tt/2gT6u3H".

Is this possible to achieve somehow? Using Javascript is no problem.