There are various kinds of endorsement, and "endoso en propiedad", as various colleagues have already mentioned, means that title is transferred via endorsement. In English, an endorsement transferring title may be either "in blank" (with only the endorser's name) or "in full"/"special"/"direct" (with the names of both the endorser and endorsee).

Here, I would assume the statement "endosado en propiedad en favor de Grupo X" means the endorsement was made specifically to "Grupo X", hence, "endorsed in full to".

However, if you feel that you can't assume this to be the case, I would simply use "endorsed to", as a simple endorsement with no further qualifying words (e.g. "conditional", "qualified", "restrictive") is understood as transferring full ownership rights (although not the obligation that the security will be honored).

Endorsement in full
Source: Encyclopedia of Banking & Finance (9h Edition) by Charles J Woelfel
(We recommend this as work of authority.)

An endorsement specifying the person to whom or to whose order the instrument is payable, followed by the signature of the endorser; known as the special endorsement in the Uniform Commercial Code.
http://www.eagletraders.com/advice/securities/endorsement_in...

Special endorsement, also known as direct endorsement and endorsement in full. This endorsement specifies the person to whom or to whose order the instrument is payable, and the endorsement of such endorsee is necessary to the further negotiation of the instrument.
A special endorsement is an unqualified endorsement, and the endorser thereof makes all the warranties to all subsequent holders in due course detailed in Section 3-417 of the Uniform Commercial Code.
https://definitions.uslegal.com/e/endorsement/




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Note added at 1 day2 hrs (2017-05-19 15:13:36 GMT)
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One other thing: instead of "definitive certificate", use "stock certificate" or "share certificate". It can only be either a "título definitivo" ("stock certificate") or a "título provisional" ("interim [stock] certificate"), so you don't need to use the word "definitive".