H1B transfer by multiple employers, whom i can start working, whom i cannot?

[lakshmisrikanth123]

I've had multiple offers from multiple employers and I'm deciding to go with a full time employment whose H1B transfer just got initiated(no LCA filed yet) and another one for which they are already ready to file my case with certified LCA in the next few days.

I asked my second employer for which the case is almost filed that i will wait until final approval before i will join but would like join the FTE job for which they are also doing premium processing for my H1B transfer but just getting started to file my LCA with the documents i've uploaded.

In this case, can i join the second employer who will get an approval in two weeks as it is premium processing and later on join the FTE job for which the premium filing will soon be approved after may be two weeks of first one getting approved?

Or should i wait for FTE employer getting a receipt and then join my dream job on receipt and notify the second employer that I've chosen a better option?