I had a pile of magazines that I wanted to give to someone in shul on shabbos. I placed the pile in the bottle of a children’s stroller, where it was mixed together with other items. I assume that although it would be possible for the person to look at the magazines in shul after receiving them, it is not likely that they would do so. In this situation, would it be a problem of borer to separate the pile of magazines from the mixture to give to the person in shul? Or would this be permissible since it would still be considered fulfilling the condition of miyad, considering that it is still possible that the person would read them immediately?
Without getting into the issue if indeed the magazines are considered a mixture on the bottom of the carriage or not, the fact that the person can use will not make it called “miyad” unless it is actually used. Every borer could be used right away, but that is not enough. There is however another reason that might permit taking it out, however it is controversial. The poskim discuss if it is permitted to separate an item from a mixture in order to give it so someone else now, when it can’t be given to him later, even though the person using the item won’t use it until later. For example, selecting some cake to give a guest before he leaves your house. R’ S. Z. Auerbach held that it is permitted, since the “use” of the object regarding the host is just to give it to the guest, and do his mitzva. A number of other poskim however argue with this, since practically the item is not being used until later. Everyone however agrees that the host cannot give the guest the cake, at the beginning of the meal. Therefore, the best thing is to give it to him after davening, and show him something inside one of them, this way both of you are using it right away.
Shmiras Shabbos Khilchoso 3 ftnt. 206, Orchos Shabbos 3- 54 in the name of R; Eliyashiv and R’ N. Karelitz zt”l, Ayil Meshulash ( Borer) 8 ftnt, 53, Even Yisroel 8-20 ( 9), Megilas Sefer -Kuntris Shmiras Shabbos 3-10.