Investigate adding a delay to message sending

[dallinski]

Is there a way to add a 1 or 2 second delay between texts contacts? I noticed if we send a message to more than 15 contacts at once, most of them fail due to using all the 4G bandwidth and resources at the same time. However if we divide our contacts in groups of 15 recipients they go out without issue. If we send them one by one after each other they go out fine. To get around this we broke all our contacts into groups of 15 but we have over 300 contacts so we have to break it up into 20 groups to get delivered successfully.