Creating Joint Tenancies
When A conveys to B and C as joint tenants (or by using other statutory-sanctioned language) the latter parties hold their title in that fashion.
Questions arise, however, when A conveys to himself (A) and B as joint tenants. At common law this could not be done because the conveyance would violate at least one of the Four Unities, namely the Unity if Time – since A was already in title when he conveyed to himself and B the two of them would not acquire title at the same moment. This anomaly required the intervention of a “straw” when a party wanted to create a joint tenancy with himself and another. This issue was addressed by the enactment of G.L.c. 184, §8:
Real estate, including any interest therein, may be transferred by a person to himself jointly with another person in the same manner in which it might be transferred by him to another person, and a conveyance of real estate by a person to himself and his spouse as tenants by the entirety shall create a tenancy by the entirety.
Although the statute now permits conveyances described above there has been discussion as to whether two (or more) persons who are in title as tenants in common can make an effective conveyance to themselves and thereby create a joint tenancy. (The statute is phrased in terms of “a person” making the transfer.) Although the statute uses this phrase, the statute also says that real estate” including any interest therein” may be transferred by such a person to himself jointly with another. The phrase "including any interest therein" is staring us in the face. The phrase clearly shows that the statute contemplates that the "person" who is acting may not be the sole owner of the property. Inasmuch as a tenancy in common consists of separate (albeit undivided) interests in the owners, each one -- each "person" -- is capable of conveying his interest to himself and his co-owner(s) and thereby create a joint tenancy as to that interest -- and there's no reason why they can't do it in one deed. It is not the number of grantor who are in a deed nor is it how many people own the property that the statute addresses but rather the removal of an impediment (the Unity of Time) created by the common law with respect to the “interest” that each owns.
A related question would be whether a person can convey title to himself and two or more persons and thereby create a joint tenancy as between all of them. I think G.L.c. 184, §8 would allow for the creation of the joint tenancy as between all three grantees. The focus of the statute is not the relationship of the two other persons as between themselves — they of course would hold as joint tenants as between themselves under common law — but rather the relationship of joint tenant of the grantor/grantee with the other person. It would seem that the reference to “another person” is not to limit the statute’s application to two people in the grantee clause —the grantor and one other person — but to allow that application, that relationship of joint tenancy, to be extended between the grantor/grantee and the other persons, regardless of how many, each of whom would be “another person,” which relationship could not be created at common law. So I think the statute permits for such a joint tenancy with three or more grantees in addition to the grantor, who is one of them.
1 The Four Unities are conditions that must exist for a joint tenancy to arise. The unities are the Unity of Time (each joint tenant must take title at the same moment), the Unity of Title (each joint tenant must have the same type of title, such as fee simple, life estate, etc.), the Unity of Interest (each joint tenant must have the same “moiety” or percentage of the title) and the Unity of Possession (each joint tenant must have possession of the entire property)
2 Some might argue that the phase, which cannot be ignored, means that the sole owner can subject an interest in his property to a joint tenancy and retain the other interests for himself, but that there has to be but one "person" who owns the property when this is done. This would become mind-boggling. Imaging A (the "person") owning the property and conveying an undivided interest to A and B as joint tenants. Then B (over whom A has no control) conveys to C. This would cause a severance and A and C are now tenants in common and under the one-person rule A (as well as C) can no longer carry out any future gifting or re-aligning of the title to the property with respect to the creation of joint tenancies, and would be prohibited from invoking the statute. The whole purpose of the statute would be neutralized!