(I am not a plant expert)
I've cut both anubias and Java fern into bits with no problem.
My gardening friends and relatives always cut back the roots by about a third when they move or split clumps; it promotes new root growth, so I do the same with my aquatic plants and it works fine.
Make sure you break each clump into pieces that have at least three or four healthy looking leaves; cut back any brown or holey looking ones, split the clump
before you trim the roots so you can make sure each new plant has enough to sustain it, and all should go well.
Most times if you look closely you can get a feeling for which bits will make a good individual plant.
Look twice and cut once
