In the book "Vayaged Moshe" (Siman 25, letter 14) it is written: "The maror that is on the plate. One should take from the maror and the chazeret that was placed on the matzah plate on the table at the time of saying 'This is the maror that we eat' etc., since it was said on it. And also according to what is written in the "Levush" (Siman 579, end of section 1) that the maror is exempted by the blessing of "borei peri ha'adama" that is recited on the vegetables in the first dipping, since the maror was also before him at the time of that blessing, and his intention was for both blessings, as explained in the Poskim (Siman 266, section 5), that each one is significant on its own, if the other kind was placed before him at the time of the blessing, he is also exempted even without directing his attention to it, and when his intention is on everything they bring, it is effective even without it being before him. Therefore, if one takes from the maror that was placed before him, he is automatically exempt in the blessing of karpas. It is understood that this is only when its taste has not completely faded. Perhaps there is a beautification, that even the guests, when they do not have enough of this maror, and there is another type specifically for them on the table, still they should eat some of this maror on the plate. I found in the book "Seder Hayom" (in the order of Bedikat Chametz, entry "and afterwards"), it is written, "Prepare a plate etc., and how to arrange it etc., one or two rounds according to the eaters, clean them well, and put them inside the vessel". And the Gra"z said that the maror on the plate is intended only for the saying of 'This is the maror that we eat'. When blessing on the maror, one should intend to exempt the maror that is on the chazeret.