Even if your items having same hsn code or same tax category is used in different type of transactions,for this no need to tag either it is cgst,sgst or igst.As while voucher entry like sale or purchase,if party belongs to same state or sale purchase type is local tax,then it will apply tax as cgst and sgst.On the other hand,if during voucher entry,party belongs to other state,then it apply tax as igst or central tax on item.
Also in different gst reports,like sale or purchase registers in gst registers,you can check hsn code wise,central or local transactions with cgst,sgst and igst bifurcations