It can be done. You just have to understand one thing well: the architecture of where the original resources reside. Which is done “in a tree” like any file on any hard disk, or like the pages of a website.
When you create a Blocs project, the program stores each resource with its path: for example, the image “IMG01.jpg” is in the “PRODUCTS” folder, so on the first Mac where the Blocs project was made, its path will be “iMacHD/Documents/MyBlocsProject/PRODUCTS/IMG01.jpg”.
When you take that Blocs project to another Mac and open it, Blocs will ask you, “Hey, man, where is IMG01.jpg now?”. Because he will look for “IMG01.jpg” in this path: “iMacHD/Documents/MyBlocsProject/PRODUCTS/IMG01.jpg” and of course he won’t find it: in fact on the new Mac you put “IMG01.jpg” in this other path: “PowerbookHD/Documents/Work/MyBlocsProject/PRODUCTS/IMG01.jpg”.
So, in order not to have problems, you just have to take care to put the Blocs project and its resources always under the SAME path on multiple Macs. But in any case, when Blocs asks you “Where is IMG01.jpg now?”, you answer with the new path and you can continue working on that project. But saving it and returning it to the first Mac as before, you’ll have to do the same work the first time you reopen the project.