This can be put in place with JS by first creating the Embedded Data Fields of "group1filled", "group2filled", "group3filled", and "group4filled". Put these at the top of the Survey Flow.
Then on the PGR question, add the below to the question's JavaScript in the OnReady section. Each time a respondent places a statement in one of the Groups and after a half second delay, the Embedded Data fields are set with "yes" or "no" based on a statement existing in the Group or not. You can then use "group1filled" is equal to "yes" as a part of Branching or Display logic.
var qid = this.questionId;
jQuery("#"+qid+" .QuestionBody").on("mouseup , touchend", function() {
setTimeout(function() {
var group1count = jQuery("#"+qid+"group0").children().length;
var group2count = jQuery("#"+qid+"group1").children().length;
var group3count = jQuery("#"+qid+"group2").children().length;
var group4count = jQuery("#"+qid+"group3").children().length;
if (group1count > 0) {
Qualtrics.SurveyEngine.setEmbeddedData("group1filled","yes");
}else{
Qualtrics.SurveyEngine.setEmbeddedData("group1filled","no");
}
if (group2count > 0) {
Qualtrics.SurveyEngine.setEmbeddedData("group2filled","yes");
}else{
Qualtrics.SurveyEngine.setEmbeddedData("group2filled","no");
}
if (group3count > 0) {
Qualtrics.SurveyEngine.setEmbeddedData("group3filled","yes");
}else{
Qualtrics.SurveyEngine.setEmbeddedData("group3filled","no");
}
if (group4count > 0) {
Qualtrics.SurveyEngine.setEmbeddedData("group4filled","yes");
}else{
Qualtrics.SurveyEngine.setEmbeddedData("group4filled","no");
}
}, 500);
});