Yw and np Martin. Always at ur disposal. I don't know if this is of help but the only solution i got, included the following colour targets (from top to bottom) Pink, Yellow, Red, Green, White and blue (bottom) that is without changing the groups or anything. I am sure that other similar solutions exist (i.e. y and pink vice versa) but feel quite positive that ur original one is impossible and that is because the white which is on top is involved to a group of equal or more than 3 and therefore when u try to place it from top right it will also move the green away from its target (always assuming that the top targets will be placed last as targets below don't have a blocking tile to help). Hope it helped and apologize if the lvl is indeed possible and I misled u. I just couldn't place them in this order.
i was very close to finishing it OMG. I think it is impossible. I'll try it again later on but can't promise anything. I will come up with a suggestion (hopefully a minor change on the groups) if i can't come up with a solution.