We are using the Activity Manager app by VersatileCapitalist to mass create tasks.

We have buttons to mass create tasks on the contact views (where whoid=contact id), and on a custom Property object (pba__Property__c)  views (where whatid=property id) - Both buttons are below.

On the Property object, we have a contact lookup field for the Property Owner (PropertyOwner__c). We would like to be able to mass create tasks from the Property view with the whoid=PropertyOwner__c.  The app has all of the functionality that we need, I am not sure how to pull/set the contact ids from the property view.

I am pretty new to code, so any help would be appreciated.

Custom Contact Button
{!REQUIRESCRIPT("/soap/ajax/20.0/connection.js")}
var records = {!GETRECORDIDS( $ObjectType.Contact)};
var returnURL = window.location.href;
if(records != null && records != ''){
mywin = window.open('/apex/activities__createTasks?Ids='+records+'&retURL='+returnURL+'&type=whoid' , '_top',
'height=400,width=600,status=yes,toolbar=no,menubar=no,location=no,center=yes,resizable=no');
mywin.focus();
}else{
alert('Please select atleast one record.');
}

Custom Property Button
{!REQUIRESCRIPT("/soap/ajax/20.0/connection.js")}
var records = {!GETRECORDIDS( $ObjectType.pba__Property__c)};
var returnURL = window.location.href;
if(records != null && records != ''){
mywin = window.open('/apex/activities__createTasks?Ids='+records+'&retURL='+returnURL+'&type=whatId' , '_top',
'height=400,width=600,status=yes,toolbar=no,menubar=no,location=no,center=yes,resizable=no');
mywin.focus();
}else{
alert('Please select atleast one record.');
}