I am planning a mini RTW with the folowing routing:

YUL-ZRH-IST-SIN(DESTINATION)-BKK-CAI-IST-ATH-JMK(STOP)JMK-ATH-MUC-IAD-YUL

I can find everything on the dates I want - all on non-scamcharge airlines - except for the JMK-ATH leg. I want to leave on May 8 but the only connection between JMK amd ATH is on May 5. Would they permit this 3 day connection or would I have to buy a separate ticket.
Thanks for any assistance.