Shouldn't the italicised part be replaced by 'among whom are'?

The presence of leaders and high profile figures from various opposition parties at former People's Action Party (PAP) Member of Parliament and Progress Singapore Party founder Tan Cheng Bock's Chinese New Year open house this year has made waves across social media.

The formation of the new alternative party, which involved "twelve likeminded Singaporeans", among which included "some ex PAP cadres", marked Dr Tan's return to politics after what he brands as "a long absence".

Shouldn't the bold part be replaced by 'among whom are'?

Thanks.