In Medina Mushaf, tanweens are shown sequentially in the cases of idgham and ikhfa. In the Unicode version of uthmani text, sequential tanweens are encoded like normal tanweens, as there is still no standard codepoint in Unicode for these type of tanweens. However, if you have
me_quran font, you can use an extended version of uthmani text in which sequential tanweens are encoded differently (see
download page).