Unable to talk on two handsets at same time when receiving a call

Unfortunately that is the untold story about cordless phones they only have the capability of 1 open line be it the handset or or the base. There are some very pricey multi line systems, I have the same system bought two extra handsets and found out too late that I can only use them one at a time! Sorry probably not the answer you were looking for but thats the reality...