How to set multiple datas?

Hello,
I have two cases where I am asking WebAssist best practices before I head off to create arrays and write my own code.

1) I have a page with a number of checkboxes in a checkbox group that once selected will be used to email to all selected recipients

<input type="checkbox" class="form-check-input"  name="CheckboxGroupGCs[]" value="<?php echo($Contacts->getColumnVal("pcEmail")); ?>" id="CheckboxGroupVendors_<?php echo($Contacts->getColumnVal("pcID")); ?>">

It looks like the Send Mail behavior is set up to use results by imploding an array of results/values on $_POST:

$Email->addTo("".((isset($_POST["CheckboxGroupGCs"]))?implode(",",$_POST["CheckboxGroupGCs"]):"")  ."");

2) What about Inserting a record of all the selected values? I would like to assign two value on Insert ($target and $emailID). Each would insert as a unique row.

Is there something already built into the MySQLi Insert Behavior or should I loop the Insert Behavior, or collect all the records into an array then Insert while looping through the array?

Thanks in advance for the guidance,