Birkat Hamazon - extra verses

My question concerns the 4 extra verse reciting by some Ashkenazi people after the end of Shir Hamaalot. They are Tehilat..., Vaanachanu..., Mi Yemalel..., Hodu.... I notice in most benchers in Israel, thse verses do not appear. howevwer it is our minhag from Chutz Laaretz to say them. My first question is: Should we continue to say them? My second question is : Sometimes we have guests who are not religious, and we show them the place in the bencher. It is confusing if they are following the place, when suddenly we are singing something that is not printed. On various occasions we have either tried to give them a bencher from abroad, which has the extra verse,s, or omit them if they have a bencher without them. What should we do? the same problem arise at the personal blessing s in the middle, when we are supposed to say something different to the guest.

Shalom Meir, The custom to add those four psukim from assorted places in Tíhilim at the end of Shir HaMaíalot before benching, is found among Jews from Germany, commonly referred to as ìYekkimî. There is no basis found in the sources (not even achronim) for this, and even the reason is unknown. All I found is a current source, where R. Shmuel Gelbard of Petach Tikva, Otzar Taíamei haMinhagim, who also found no rationale, creatively suggests that each of the verses correspond to one of the four brachot in the benching. Regarding whether to continue saying it or not, in general, the rule is that upon coming to a new country, one should accept upon himself all of the local customs, whether they are lenient or whether stringent (Psachim 50b) and should not change from what is done (Mishna Brura 468, 14). On many issues, Eretz Yisrael has no set minhag, and in such cases everyone should follow his previous family custom. But in this case, the clearly predominant custom in Eretz Yisrael is not to add them and therefore itís better not to continue saying it (unless you are a yekke, and in that case, if you wish, you can continue saying it, relying on the fact that it is being done in private, where changing from the local custom is less problematic, see Mishna Brura, ibid). Accordingly, by not adding these psukim, that also solves the confusion regarding your second predicament! With Love of Israel, Rav Ari Shvat