time to sell one of our investments?

we started out in investment property 7 years ago. we owned most of our ppor except for a line of credit which we used to finance a business. we then borrowed against the equity in the ppor to buy another house which we moved into and made the first one into our investmant property. we then borrowed from equity in both to buy a third property with a 10% deposit (of cash) but with the same bank. they joined all the 3 loans together. we then bought a third IP with no deposit using equity from the first 3. people are telling us that we should not be doing this. We have no tennant in our 2nd IP at present and we are thinking of selling it to pay off one of the loans and release some equity to put a cash deposit on another property with a different bank. my question is; what is the problem with having all the loans linked together? my partner thinks that even if we go to a different bank with a cash deposit, that if for some reason we can’t pay for one of the loans that the second bank can forclose on us and sell the properties that the first bank has mortgages over. i’m confused. can anyone help?