You may as well choose it just between T1, T2 and T3, however it's as fast to wander. Amongst T4 and T4S, make use of the automatic educate. The metro also connects the two complexes however, you'd need to purchase a ticket for €3. There are actually other transfers https://norahv935nif6.blogspothub.com/26541036/the-ultimate-guide-to-madrid