The phrase "appearing to join" is correct and usable in written English.
It can be used when describing someone or something that seems to be in the process of becoming part of a group or activity.
Example: "The new members were appearing to join the discussion, eager to share their thoughts."
Alternatives: "seeming to join" or "looking to join".
Another image from the videotape depicted Mr. Ortiz from the back with his shirt off and hands thrust in the air, appearing to join in the melee.
Thomas Mulcair, the NDP's leader, accused Mr Harper of appearing to join forces with Mr Assad, "a brutal dictator and war criminal", even though the bombing would happen without the Syrian leader's approval.
Appearing to join the fray, Death Valley National Park tweeted about the discrimination that led to Japanese internment camps during World War II at about the time on the same day Trump released harsher immigration screens aimed at Muslim refugees.
Cameron faced further criticism when he told one of his own MPs, Nadine Dorries, that he knew she was "extremely frustrated", before appearing to join in with the mirth that his double entendre had provoked on the Tory backbenches.
Hammond later appeared to join him, although BBC2 controller Kim Shillinglaw refused to rule out their return.
Suddenly, the first man, Philip Neal, appears to join her in the increasingly passionate waltz section.
SARS now appears to join a number of other infectious agents that bats can transmit.
This week the Bank of Japan, under pressure from a new government, appeared to join the club of the bold.
Midway through the set, he plays Blackbird alone on an acoustic guitar and the entire stadium appears to join in.
Riot police officers deployed to stop the clashes outside the cathedral appeared to join rock-throwing youth battling Christian mourners inside.
Mr Ban appeared to join the US and Egypt in calling for an unconditional ceasefire, to be followed by talks on a possible new border arrangement for Gaza.
