Adding a filter to the People page (browse.php)

I'm currently developing a website, where I'm using Dolphin as the basis for what will become a Volunteerism website.

I need to add a filter control to the People/Browse page.The objective is simple. I have two types of members on the site: Volunteers and NonProfits. Everything on the website is free, so there's no paid membership schemes.

I want to provide users on the website with an overview of all NonProfits and Volunteers on the site. Therefore, there needs to be a filter control on the top of this page where a user can Filter the members on the page. There are currently 3 filters: sex, age and country (off to the right side of the page). This will be the fourth and needs to be placed on the top where members are displayed.

The thing is, this filter does already exist on the Admin side. The Members page in the Admin section does have a Filter at the top of the page where you can filter for sex, active, couples, etc .... including membership levels.

I want to bring this functionality to the Browse page on the front end.