You can write whatever agreement, clause you want.

But in property, if it is joint name, then both needs to sign before the property can be sold, or do whatever on the property.
This is ultimate.

So if face off time, do you think the other party still want to fulfill the clause set in the agreement?
For eg.
You write both party must equally pay the instalment, now the other party now refuse to pay,
What action you can do?
I only know the first thing bank will do is auction the property if no instalment being paid.