Do those who pray to saints ascribe to them the quality of being able to hear many people at once? I mean, there could be thousands of Orthodox Christians at this moment praying to, say, Saint Blessed Xenia of St. Petersburg, and there could probably be even more of Catholic Christians praying right now to, say, saint Patrick, let alone Mother Mary. Does that mean that all those saints have the All-knowing God's ability to hear all of those praying to them, distinguish their prayers one from another, and later adequately act on each one of them accordingly?
Time has no meaning in heaven, there is probably a more precise Thomistic answer for this question bit that should suffice.  If time is meaningless then &quot;at the same time&quot; is meaningless. I'll get confused if I write any more about that.

Is it possible, O Lord, that, since thou art in eternity, thou art ignorant of what I am saying to thee? Or, dost thou see in time an event at the time it occurs? If not, then why am I recounting such a tale of things to thee? Certainly not in order to acquaint thee with them through me; but, instead, that through them I may stir up my own love and the love of my readers toward thee, so that all may say, &quot;Great is the Lord and greatly to be praised.&quot; I have said this before and will say it again: &quot;For love of thy love I do it.&quot; So also we pray -- and yet Truth tells us, &quot;Your Father knoweth what things you need before you ask him.&quot;
Consequently, we lay bare our feelings before thee, that, through our confessing to thee our plight and thy mercies toward us, thou mayest go on to free us altogether, as thou hast already begun; and that we may cease to be wretched in ourselves and blessed in thee -- since thou hast called us to be poor in spirit, meek, mourners, hungering and athirst for righteousness, merciful and pure in heart. Thus I have told thee many things, as I could find ability and will to do so, since it was thy will in the first place that I should confess to thee, O Lord my God -- for &quot;Thou art good and thy mercy endureth forever.&quot;
St. Augustine of Hippo - Confessions Book 11, Chapter 1.

We not only believe that the saints can hear and deliver our prayers to God. We believe all the angels and all the saints are present at every Mass.