Domestic or international flights? Domestic flights usually don't have MPM, they have routing rules which dictates which cities you can connect through. The routing rules are not shown on AA.com.
For example, SAN-JFK
Code:
MAP CONSTRUCTED LEFT TO RIGHT AND RIGHT TO LEFT
1. SAN-PHX/LAX-WAS/PHL/NYC/DFW/CLT/CHI/BOS-NYC
2. SAN-PHX/LAX/DFW-WAS/PHL/NYC/CLT/CHI/BOS-NYC
3. SAN-PHX/LAX/DFW/CHI-WAS/PHL/NYC/CLT/BOS-NYC
4. SAN-PHX/LAX/DFW/CHI-NYC
5. SAN-PHX/LAX-WAS/PHL/NYC/DFW/CLT/CHI/BOS-CLT-NYC
6. SAN-PHX/LAX/DFW-WAS/PHL/NYC/CLT/CHI/BOS-CLT-NYC
7. SAN-PHX/LAX/DFW/CHI-WAS/PHL/NYC/CLT/BOS-CLT-NYC
8. SAN-PHX/LAX/DFW-NYC
9. SAN-PHX/LAX-NYC
So, you aren't allowed to go SAN-MIA-SEA-JFK on this fare.