Hi:
First, speak with the vendor providing your pager equipment. They may be able to provide a unix solution.
Probably they can't, but most of the pager vendors now support email in some form.
With proper setup, Unix can support email, so you could potentially send email to anybody using mail or mailx.
But now you're getting into sendmail configuration and mail server setup - something NOT in my area of area of expertise.
Regards,
Ed