All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Whoever acquired any kind of knowledge and withheld it from the people who need it commits a great sin.
Allaah The Almighty Says (what means): {Indeed, those who conceal what We Sent down of clear proofs and guidance after We Made it clear for the people in the Scripture - those are cursed by Allaah and cursed by those who curse.} [Quran 2:159]
Moreover, it was narrated on the authority of ‘Abdullaah ibn ‘Amr, May Allaah Be Pleased with him, that the Prophet, sallallaahu ‘alayhi wa sallam, said: “report from me, even if it is one verse.” [Al-Bukhari]
Furthermore, disseminating knowledge among people is really one of the matters that will benefit its doer continuously even after his death. It was narrated on the authority of Abu Hurayrah that the Prophet, sallallaahu ‘alayhi wa sallam, said: “When a man dies, all his good deeds come to an end except three: an ongoing charity; beneficial knowledge and a righteous child who supplicate (Allaah) for him.” [Muslim]
According to these texts mentioned above, you must not conceal the Islamic magazine that you did from your colleagues, especially if you know that it will be religiously beneficial for them. Do not let your fear of envy stop you for there are many preventive measures against envy that you can use.
Allaah Knows best.