Type character in name and make it invisble

my website is using MyHome theme. I need to write identical names for two search fields. Here - https://komand.suvenirite.net/dava-pod-naem/?offer-type=rent And here- https://komand.suvenirite.net/prodava-offer-typesalecitygrad-sofia/?offer-type=sale Under the search field ВИД НА ИМОТА (the first one) The need for that is that the system gets confused if there are identical names even thought their parent fields are different, but for the client they need to appear the same.

Yes, I have tried changing the structure, but of no use. The client is unbeatable. Adding simple invisible character does not work. Adding space or removing the - does not work either. It should be drastic change in the name for the theme to accept it.

What I have achieved until now with some javascript and css:

jQuery.fn.highlight = function (str, className) {    
    var regex = new RegExp(str, gi);

    return this.each(function () {
        this.innerHTML = this.innerHTML.replace(regex, function(matched) {return span class=\ + className + \ + matched + /span;});
    });
};

$(span).highlight(___,highlight);

CSS

span.highlight {
   color:#FFF;
    visibility: hidden!important;
    display: none!important;
}

This doesn't work :

button.btn.dropdown-toggle.btn-default span.filter-option.pull-left span.highlight {
   color:#FFF;
    visibility: hidden!important;
    display: none!important;
}

Here it can be seen how it works - https://komand.suvenirite.net/dava-pod-naem/?offer-type=rent Under the field ВИД НА ИМОТА 1-стаен___

As ___ these characters should not be seen but when active they are.

Please, can anyone help me?