jQuery Grid Plugin - jqGrid

Hello, my first post here.

I am using several grids on a single page that have a single custom search form for all of them. Sometimes I need to load a new grid into the page and I want to have the set filters applied. I try to achieve this by adding "?_search=true&" + $(".filterform").serialize() to the end of the url and it looks like a perfect search request. The problem comes when the grid adds the _search=false parameter and then I have two _search parameters on the url. Since the one added by the grid is the last one, is the one that the server gets.

Is there any way of changing this behaviour? I could change things on the server side, but want to use the _search parameter as it is meant to be. By now I just trigger the search once the grid is loaded, but that means and extra grid reload and an extra server request.

Any ideas?? Thanks in advance!