In 2002, the Taiwan Solidarity Union, a party with about 10% of the Legislative Yuan seats at the time, suggested making Taiwanese a second official language. This proposal encountered strong opposition not only from Mainlander groups but also from Hakka and Taiwanese aboriginal groups who felt that it would slight their home languages, as well as others including Hoklo who objected to the proposal on logistical grounds and on the grounds that it would increase ethnic tensions. Because of these objections, support for this measure was lukewarm among moderate Taiwan independence supporters, and the proposal did not pass.
Try to answer this question if possible (otherwise reply "unanswerable"): What did Mainlander groups suggest in 2002?
unanswerable