Unfortunately the MAILTO keyword is a manual function where a user does need to click on it, before your de facto email app pops up with the relevant fields populated, before you manually click 'Send' to send the email.
However there is a workaround for your request that doesn't involve MAILTO.
You can create a module with a numbered list (depending on your requirements, this numbered list can be replaced by a combination of lists) and line item. The numbered list could be a technical list with say 100 members, and the line items are text formatted to capture the TO, CC, BCC, Subject, Mail Body. You can also insert additional Boolean line items which shows/hides different rows based on dynamic selection requirement mentioned in your question.
You can then have an Anaplan Connect in an enterprise server scheduled to export the module above into a csv/txt file. Then a program is scheduled to send the csv/txt file to a SMTP server which then sends the email out.
Well with integration what I meant was to send email automatically without any human interference. The email which I am sending currently to users do not have any sort of exports but it's a reminder to those users to complete there pending task.
I already have everything in place to select only those users who have not completed there task but my reason for asking this here was I have to do this every 4 hours so if I could integrate it or may be set some timer to send this email automatically.
In my response, i mentioned "You can then have an Anaplan Connect in an enterprise server scheduled to export the module above into a csv/txt file. Then a program is scheduled to send the csv/txt file to a SMTP server which then sends the email out."
The scheduled is done by scheduling Anaplan Connect to run every 4 hrs, before another program sends the csv/txt file to a SMTP server.
As mentioned, this is a workaround that requires some scripting, since we don't have anything in Anaplan at the moment that does scheduled email sending.