I am looking for help to simulate below scenario in Factory flow simulation, is there a logic or simpler way to achieve below objective.

In and Out flow of part is shown in below loop.

Objective 1 - 

• at Station E, F, G operator need to assemble a fixture (please note - at either 1 of these only fixture will get assembled, so if it assembled at E then F and G will skip).
• If all 3 stations (E, F, G) are vacant, then part will directly go to last station G and will wait for operator to complete fixture assembly on part.
• Operator take 10 sec to install fixture.
• at M, N, O above assembled fixture will get removed (please note - at either 1 of these only fixture will get removed, so if it removed at M then N and O will skip).
• Operator takes 10 sec to remove the fixture.

Objective 2 -

• Once part accumulate at station M,N and O (at all 3) then only operator move from other side to remove fixture.
• Similarly once all 3 st. E,F,G are having part then operator will walk other side to install fixture.