Hello julieb378,
Thanks for using Apple Support Communities.
If you're getting the same phone call on multiple iPhone's, then it indicates you have cellular calls enabled with Continuity on your iPhone that doesn't have the other's phone number. Simply deselect this phone number as an option on your iPhone, and the iPhone should stop ringing when the other does.
To turn off iPhone cellular calls on your iPad or iPod touch, go to Settings > FaceTime and turn off iPhone Cellular Calls.
On your Mac, open the FaceTime app and go to FaceTime > Preferences. Click Settings and deselect the iPhone Cellular Calls option.
Use Continuity to connect your iPhone, iPad, iPod touch, and Mac
Take care.