I have found a solution with this template :

Value VPLS (\d+)
Value VPLS_NAME (\S+)
Value Required SAP_LAG (lag-50:1923\.(6|7)\d+)
Value List SDP (\d+)

Start
 ^\s+vpls\s${VPLS}\sname\s${VPLS_NAME}\scustomer\s\d+\screate
 ^\s+sap\s+${SAP_LAG}\s+split-horizon-group\s+"SPLIT_HORIZON"\s+create -> Meshsdp

Meshsdp
 ^\s+mesh-sdp\s${SDP}:\d+\screate
 ^\s{12}exit -> Meshsdp
 ^\s{8}exit -> Continue.Record
 ^\s+vpls\s${VPLS}\sname\s${VPLS_NAME}\scustomer\s\d+\screate -> Start