As of Oct. 31st, The State of Jalisco passed the Law of Cohabitation, which will come into full effect January 1, 2014.

Free cohabitation is very similar to marriage and has the same benefits of common-law marriages with a few distinctions regarding adoption and custody of minors not biologically their own and the fact that the parties execute a contract before a Notary Public instead of a judge.

The Law of Free Cohabitation grants two OR MORE adults (caps are my own), regardless of gender the right to make a life together. They can choose whether or not to pool their property, and all have the same support duties, enjoy the same federal, state and local benefits and rights (ie. social security pensions, tax deductions survivorship and inheritance rights, etc.) as married couples do.

Married persons are not eligible, and individuals may not be party to more than one cohab contract at any time.

Mexico's Supreme Court has ruled that same sex marriages are legal throughout Mexico, and it has ordered all municipalities to marry same sex couples, declaring that gender requirements to marry are a violation of the partie's Constituional and human rights.

All states in Mexico, and the Federal Government, are obligated to recognize the validity of marriages, civil unions, and now free-cohabitation contracts anywhere they are legal-in Mexico or abroad.

So now, for the first time I'm aware of the boundaries of legal cohabitation with full rights similar to those of married couples, are extended further than same sex, to include groups! So far as I know there is not a limit to the number of people allowed to enter into the cohabitation contract. I see this as the beginning of the future forseen by R.A. Heinlein, wherein group and several other forms of marriage are no longer odd, but the norm.

Now if only the rest of the world would join Mexico in the 21st century in this respect.