No, a dipole has one element attached to the center conductor, the other attached to the shield. Your tee would put both elements on the center conductor. Odds are the received signal would be worse due to phasing issues than just a single antenna.
One thing you could do (whether it's useful is another story) is use the correct lengths of coax between the two antennas and the tee to create a phasing harness. Depending on how you phase them together, you could create a null spot, or make them directional. A friend had a hand-held "fox hunting" setup like that, but otherwise probably not much use...
