They camp in al-Sharaa’i’ during Hajj and are asking about joining and shortening prayers and Jumu’ah prayer
Question

                We are members of the Armed Forces and we participate in the Hajj Mission every year; we stay in the area of al-Sharaa’i for approximately one month, and we are formed into groups that take turns on guard duty in a place that is far away from the camp. Those who are not taking their turn on guard duty stay in the tents, in a state of preparedness for any emergency. Hence we hope that you can advise us as to how those who are staying in the accommodation should pray. Should we join or shorten our prayers or not? Some of the camps have mosques and they want to establish Jumu’ah prayer. Is it obligatory for them to do Jumu’ah prayer? If there is a neighbourhood next to us where Jumu’ah prayer is offered, should we pray with them?.
Praise be to Allah.
      So long as you are going to stay in al-Sharaa’i’ for more 
      than four days, then you should offer prayers in full without shortening 
      or joining them, because you come under the same ruling as residents. If 
      you intend to stay for four days or less, or you do not have any 
      particular length of time in mind, then you come under the same rulings as 
      travellers, and you may shorten the four-rak’ah prayers and join them. 

    With regard to Jumu’ah, you have to pray it in the nearby 
    mosques if Jumu’ah prayers are held there.  

    And Allah is the source of strength. May Allaah send 
    blessings and peace upon our Prophet Muhammad and his family and companions. 
    End quote. 

    Shaykh ‘Abd al-‘Azeez ibn ‘Abd-Allaah ibn Baaz, Shaykh ‘Abd al-Razzaaq al-‘Afeefi, Shaykh ‘Abd-Allaah ibn Ghadyaan