Sheikh `Abd al-Rahmân al-`Ajlân, lecturer at the Grand Mosque in Mecca
It is lawful to perform i`tikâf in any mosque where congregational prayer is held.
However, if the person intends to observe i`tikâf on a Friday, then it is preferrable for for that person to do so in a mosque where the Friday prayers are held. In this way, the worshipper will not be obliged to leave i`tikâf in order to go to another mosque to attend the Jumu`ah prayer.
And Allah knows best.
Source: Islam Today