Is it permissible to invite doctors to scientific symposia organized by a pharmaceutical company in recreational tourist locations, knowing that they contain elements of temptation (fitna)? And does the inviter bear a religious sin for doing so, even if they do not attend, given that this is a fundamental part of the job?

You are not permitted to invite others to seminars that contain sins and temptations, as this leads to them falling into sin. The Prophet, peace and blessings be upon him, said: "And whoever calls to misguidance will have a sin similar to the sins of those who follow him, without diminishing their sins in the least." Furthermore, inviting people to sin falls under the Almighty's saying: "And incite whoever you can among them with your voice." You should search for another job that does not contain any Shariah prohibitions, for whoever fears Allah, He will make for him a way out and provide for him from where he does not expect, and whoever gives up something for Allah, Allah will compensate him with something better. Also, you must love for your brother what you love for yourself, so if you dislike attending these seminars for yourself, then do not invite your brothers to them.