Your Wish:

"Restrict callers to selected modems on a shared line"

Flexie TelCo Switch Modem Router Switch

Programmable remote selection and control of three ports. Access via Touch-Tone. Optional remote AC power control and reset button reboots.

MRS Modem Router Switch

Directs inbound modem calls to any of 8 different modems. Port selection through DTMF or CHALLENGER KEYS. One & two line models.