Typically, if two fields have the same name, the values would convert with the Lead, onto the Opp
However, iām not sure if there is a good way to move across relationships out of the box.
Iāve tried to play around with Workflows, trying to relate the Projects to the Opportunities via the āModify Recordā actions, but have been unable to get any results.
It might be something that would need some custom work, unless anyone else has any ideas?
If you do need to do some custom work, I imagine you could do this with either a Logic Hook or by customizing the Lead Convert functionality.
Iāve found some forum posts of users performing some of both, that might give some ideas as to how it could be done:
Perhaps some of the above would be a good place to start?