video phone door switcher

[kanwal_diku]

hi
can anyone plaese tell me where to get a circuit for multi-appartment video door switcher.

basically i want a switcher that can direct the feed of a single camera(instaleed at the front door) to the screen (installed in d multiple appartments) which the user choses.
hope you understand what i am lookin for and hope i get get some useful information for the same