Super Wierd Time Signatures

I don't know if this is possible, but how would I go about making a time signature like 4/3 or 3/7. I know musescore lets you create custom time signatures but it only allows for denominators that are 1, 2, 4, 8, 16, 32, 64, and 128. Is there a workaround that allows denominators such as 3, 7, 9 etc. Thanks in advance!