Line based Extended Kalman Filter for localization : Measurement Jacobian
How are you modeling the state transitions? How are you modeling the output equation i.e. How does the state get to the measurements? Without that information, we can't tell you much about how to get your Jacobian right. 

Usually, with multiple measurements, you just stack the state / observations so things go from $2 \times 3$ to $2\times 24$ in the case of 8 measurements, instead of augmenting in another dimension.