You could use an Evaluator column that parses the emojis and displays them via markup.
if (operation != "markup") return desc;
d = desc;
d = RegExS(d, ":red_circle:", "<#FF0000>âš«</#>");
d = RegExS(d, ":green_circle:", "<#00FF00>âš«</#>");
d = RegExS(d, ":yellow_circle:", "<#FFFF00>âš«</#>");
return d;
XML
<?xml version="1.0"?>
<evalcolumn align="0" attrrefresh="no" autorefresh="no" blurrable="no" customgrouping="no" foldertype="all" keyword="descmu" maxstars="5" namerefresh="no" nocache="no" reversegroups="no" reversesort="no" supportmarkup="yes" title="descmu" type="0">if (operation != "markup") return desc;
d = desc;
d = RegExS(d, ":red_circle:", "<#FF0000>âš«</#>");
d = RegExS(d, ":green_circle:", "<#00FF00>âš«</#>");
d = RegExS(d, ":yellow_circle:", "<#FFFF00>âš«</#>");
return d;</evalcolumn>
