To give a better answer, we would need to know more about your LNBs.
But, to answer your basic question, a "T" connector in the coax will not work under
any circumstances.
Each of your LNBs needs to get power from the receiver, and it needs to be able to put its signal on the same coax for the receiver to decode.
Tying the outputs of two LNBs together, will probably not damage anything, but it cannot work.
Alternative ways, would be to connect each LNB to the receiver, one at a time.
Tune , adjust, aim your dish for best signal.
Do the same for each LNB, but only that one LNB.
Then, connect both LNBs through a simple diseqc switch (or possibly a 22khz switch) to the receiver.
Now, you must adjust the receiver setup to select each LNB via the switch.
We have a FAQ (frequently asked question) thread on
basic switches, which should help if you are not very familiar with them.
If you are still confused, please ask again and I'm sure we can solve your problem. - :up