Increase Custom Message Text character limit

Currently, there is a string limit of 25 characters (must have a space every 25 characters) for Custom Messages.  With use of texting / email (in conjunction with the callouts/SIRENS), we'd like the ability to include some hyperlinks in the messages (at least the email) we send out, especially if it directs employees to refer to a linked document.  The 25-character limit prevents this.  (We have tried URL shorteners, but many of them are blocked due to cyber security reasons)