So you are fortunate enough that you have both sightings, and some depth in your volunteer base for responding to sightings. Or the family with the lost dog has friends, neighbors and extended family members that are ready to jump in and help. This is good!
But when a sighting comes in, if there are three people that you want to respond, or at least to notify to see if they can respond, you want to notify them all as quicky as possible. So here's a quick way if you have the sighting call taker at a computer.
For each first responder, collect the cell phone and their carrier name. Then determine the address at which you can send a short email from your email address that will be recieved as a text message by the first responder. I found the information by searching on "email to text"; plenty of resources came up. Here are the main providers, and what your emails would need to look like:
Provider Format
Sprint phonenumber@messaging.sprintpcs.com
Verizon phonenumber@vtext.com
T-Mobile phonenumber@tmomail.net
AT&T phonenumber@txt.att.net
So for example, if you have someone whose number is 800-555-1212 and their carrier is T-Mobile, then you email them at 8005551212@tmomail.net.
Obviously if you need to notify only one person of a hot sighting that you want them to respond to, this isn't a handy trick. But it works great if you have about 3 or more, and you have a computer to use to notify people. Even people that don't like to text back can at least read a text.
Give it a try the next time you have several people to notify that you have sighting calls to respond to.
