I think this will work. (I normally use another version of spice, but I think this is standard syntax):
R1 2 0 1000
R2 3 0 10Meg
X1 1 0 2 0 3 T_12
VV1 1 0 dc 0 ac 1 0 sin(0 1 1000 0 0 0)
.SUBCKT t_12 1 2 3 4 5
* *1, 2-- primary winding, *3,4-- secondary terminal, 5-- center tap
Rs1 1 11 6.600e+001
Rl2 31 3 3.600e-001
Rl3 41 4 3.600e-001
L1 11 2 1.015e+001
L2 31 5 1.223e-001
L3 5 41 1.223e-001
K12 L1 L2 9.856e-001
K13 L1 L3 9.856e-001
K23 L2 L3 9.856e-001
.ENDS