[HELP] Expedition - how to change min number of members in expedition

Hi everyone.

I have tried to solve this but to no avail. Due to low population in my server, I intend to reduce all expedition entry to 2.

For now, chaos HT, chaos ZK, PB, vonleon and cygnus need a min of 3 - man expedition in order to enter.

Is there any way I can change it to 2-man expedition to enter?

I tried to find the function that determines how many man required to enter expedition but is unable to.

Could the function be in the NPC that gives that particular expedition? (EG: Mark of the Squard, for Horntail)