Carrying in a partially shared apartment on Shabbat

Question

I read that carrying between different units of a multi-family apartment might be a problem on Shabbat. I seek the general rules that will govern the following types of situations:

(To illustrate, I will use the following artificial floor plan:

where: 1 is a bedroom (Jewish); 2 is a bedroom (Jewish); 3 is their common area; 4 is their kitchen; 5 is a bedroom (not Jewish); 6 is a bedroom (not Jewish); 7 is their kitchen; 8 is their common area; 9 is a shared entrance way; 10 is the outside. All rooms are totally enclosed by walls and doors.)

1. Carrying between all Jews' apartments (1 or 2), and a common area (3).
2. Carrying between a common area shared between Jews and non-Jews (3 into 9).
3. Carrying between the Jewish and non-Jewish areas (3 into 8).
4. Carrying between the non-Jewish apartments and non-Jewish common area (5 or 6 into 8).

Additionally, do the following things matter?

• The type of common area (space, some useful space like a kitchen, laundry, what-have-you)
• The number of people in each individual apartment
• The level of separation between Jewish- and non-Jewish-owned areas

This appears to me to be a marr'it eyin issue (as seen from The 39 Melachot books page 1318, though other sources would be appreciated). As such, does having some sort of signage or similar device remove the prohibition?

(My understanding is that so long as it is all one totally enclosed space it is all one reshut hayachid and thus carrying would not otherwise be a problem.)

Answer 1

The kitchen (#4) combines 1, 2, and 3 as a de-facto eruv chatzerois. (Same for the other side.) See: http://www.yna.edu/archive/s_ask58e-04.html and http://belogski.blogspot.com/2007/07/carrying-on-shabbat-in-hotels-and.html

People who live around a courtyard and all eat at one table, even if each has his own house, do not need a Eruv, because they are like members of one household. Similarly, if several people eat in one room, each at his own table, even if each has his own room. (Shulchan Aruch Orech Chaim 370)

Between 9 and the other two residences you need an eruv chatzeiros - other than the roof over 9 (if it has one) that's the classic case where you need one. (Unless you all eat together in room 9.)

Is this a rental? If it is that may make handling the non jewish ownership easier.

I don't believe this: "My understanding is that so long as it is all one totally enclosed space it is all one reshut hayachid and thus carrying would not otherwise be a problem." is correct. An eruv chtzeriros is always over private property (reshut hayachid) - but it's private property of different people.