Yes, it is possible to combine the two raster maps. One approach is to use a process called reclassification, which involves reassigning the values of the cells in the LULC map based on the values in the urban map. Here's how you can do it:
Reclassify the urban areas in the urban map to match the LULC classification in the LULC map. Since the value for urban in the urban map is 1, you can use a reclassification tool in your GIS software to reclassify all pixels with a value of 1 as 6, which is the value for urban in the LULC map.
Use a raster calculator to combine the two maps. In the raster calculator, you can create a new raster layer by multiplying the reclassified urban map with the LULC map. Since both maps use the same value (6) to represent urban areas, multiplying the two maps will result in a new raster where all pixels that are urban in both maps will have a value of 36 (6 x 6).
Apply any additional modifications to the LULC map as needed. Once you have combined the two maps, you can make any additional modifications to the LULC map as needed, such as reclassifying other land cover types or adjusting the boundaries of urban areas.
Note that the specific steps and tools for reclassification may vary depending on the GIS software you are using. However, the basic approach of reassigning values based on another raster map should be similar across most GIS software.