Hi @Bassem,
It is only possible to do this right now in external software. If you have two local refinements in the same reference frame (i.e. no particle origin shifting has been done in Volume Alignment Tools, for example), you might be able to follow a similar path to the quoted reply below. That is, you could take the maximum local resolution value between each of the local resolution maps, for each voxel in the map. The local resolution maps output their results in Angstroms (not inverse Angstroms), so you would want to use the minimum value in this case. This could be done with the vop minimum command in UCSF Chimera.
I would encourage you to review some previous discussions on the forum before proceeding with this, as some users (see above) have recommended to keep the distinct maps (and hence their local resolution maps) separate when depositing. You may also find this thread helpful: Can local refined map be combined with the original map?
Best,
Michael