video conferencing over LAN

hi everybody, need some guidelines regarding videoconferencing over a LAN nwtwork in our hospital. tried using windows media encoder; two problems 1. doesnt seem to work without a net connection on 2. good for only broadcasting. we need two way audio conferencing as well along with one way video; if two way video is also possible then thats a plus. any ideas about adobe connect pro? will it serve our purpose? any pther software/hardware requirement. we have an established LAN network all over the hospital.
thanx

doc