They're divs one after another so you could float them with CSS and set their width to 50% for example to have 2 side by side per row. Right click and click inspect element to review their HTML structure for CSS classes and IDs that can be used in your styling. The HTML structure can't be changed as it's dynamically generated. Example as follows.
Code:
.cbUserListSearchFields .cbFieldsContentsTab:after {
content: '';
clear: both;
}
.cbUserListSearchFields .cbFieldsContentsTab > .cb_form_line {
float: left;
width: 50%;
}
.cbUserListSearchFields .cbFieldsContentsTab > .cb_form_line > label,
.cbUserListSearchFields .cbFieldsContentsTab > .cb_form_line > cb_field {
display: block;
width: 100%;
}