Run button - Mailto multiple selections by end user on grid application

Having no luck, any help would be appreciated.

I created a Grid application showing the following information: Name. Contact, Email, Business Type.
The end user needs to be able to search for specific types of businesses then send an e-mail to some or all of records that return. Unfortunately they are mandated to use their own company e-mail software so using the internal scriptcase simple e-mail will not be allowed in this situation. However, using the simple html “mailto” function works because it opens their existing e-mail software and populates the “To” line with the e-mail address. But, it only does this for one record at a time.

I need to create a run button that will allow the end user to select one or more records from the record list.
The button will need to store the selected e-mail addresses from the Email field, then open the clients e-mail service (Outlook, Yahoo, etc), populating the “To” field with the data that was selected.
I need this to work just like the Email button on a form does. Any help is much appreciated! Thanks!!

I would try this in the run button
OnRecord: keep appending the selected records email addresses to the same variable (using ; as a separator)
OnFinish: echo the variable using the correct syntax to create the html MailTo element (see here)

So after selecting the records and pressing the run button, your users will see the MailTo link they have to click on to acutally open their email client

Thanks @robydago This is what I was trying to do but had no luck programming the OnFinish aspect of it. Will keep trying.