You an use a 1031 exchange on the portion allocated to the investment side.  

anyone have any experience with investment property loan exchange

You'd need about 250-300k for a down payment for a starter duplex which may work better for you since you can utilize one side as a long term rental and the second side as an STR which you can use as you please but remember if you do a 1031 exchange you'd be limited on how much you can actually use that property to still be considered an investment and not a second home.

My husband did a reverse 1031 exchange on a property over 20 years ago. 

@Dan H.Most GP’s don’t allow it, especially for accredited investment offerings because the purchase must also be accreditedWe have a reg an offering and have a death and disability clause that gives an out and have had one case where this occurred at of 700+ investors.As someone else mentioned, you would essentially be setting up an exchange which would require finra licensing and the licensing costs alone would make it cost prohibitive

Can anyone recommend a reputable 1031 Exchange Company?

@David RutledgeRealtor here who works with investors in both the STR and LTR markets.Consider my local area of Long Beach, CA.Most of LA and Orange County are STR-unfriendly but Long Beach just opened it’s regulations to allow non-owner occupied STRs.Aside from being a beach town in it’s own right, it is quickly becoming an aerospace hub.

Hello just wonder has anyone had any experience using Loan Exchange??

that I think would need to get involved to make an exchange like this legally binding. 

Sure, a seller may offer you 5%, but if they're smart they will ask for a higher sales price in exchange for giving you an advantageous loan.